SENSOR PLATFORM

Abstract

Provided is an FET-type sensor array. In the FET-type sensor array, a plurality of FET-type sensors are arranged at arbitrary distances from one reference point, and the same areas of the FET-type sensors are arranged to face the reference point. The FET-type sensors includes a control electrode, a floating electrode, a sensing material layer arranged between the control electrode and the floating electrode, and source and drain regions formed on both sides of a lower portion of the floating electrode. In the FET-type sensor array, through miniaturisation of FET-type sensors constituting the sensor array and new design of air layers in the peripheries of micro-heaters built in the sensors and sensing material layers, power consumption of the micro-heaters can be reduced. In addition, the sensors can be efficiently arranged to reduce the area occupied by the sensor array, and the sensing material can also be heated by the adjacent micro-heaters, so that the total power consumption can also be reduced.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an FET-type sensor array, and more particularly, to an FET-type sensor array including silicon-based MOSFET (metal-oxide-semiconductor field-effect transistor) type sensors having a floating electrode formed in a horizontal direction on a control electrode, an FET-type sensor array including FET-type sensors having a built-in micro-heater, and a method of manufacturing the same capable of ensuring thermal and mechanical stability and greatly reducing size and total power consumption through creative and efficient arrangement of the sensors and being applied to sensors for sensing various gases.

2. Description of the Related Art

In recent years, gas sensors having various structures have been developed to sense various gases including harmful gases which cause environmental problems. As the gas sensors, there may be exemplified resistance-type gas sensors having a semiconductor as a sensing material, gas sensors using an infrared ray, optical gas sensors, and FET-type gas sensors. Particularly, among these gas sensors, the FET-type gas sensors capable of being miniaturized, operating with lower power, and being incorporated with CMOS circuits such as low noise amplifying circuits have been increasingly studied.

In the field of the gas sensor array, most of the gas sensor arrays that are used to distinguish, various gases by using a pattern recognition circuit or software are mainly based on resistance-type gas sensors in the related art on which different sensing materials are deposited. On the other hand, during the gas sensing, gas sensing characteristics are changed depending on a change of external environment such as a concentration of gas and an ambient temperature as well as a gas type. Particularly, the ambient temperature is a factor affecting gas sensitivity and gas reaction and recovery speeds.

A gas sensor has the optimum temperature at which the sensitivity of the gas sensor is maximized for each gas sensing material and each kind of gas to be sensed. In general, the higher the ambient temperature, the faster the gas reaction and the recovery speeds. In the field of the gas sensors array in the related art, studies of improving gas sensing characteristics by introducing various types of heaters have been made.

The FET-type sensors can foe applied mainly to gas sensing. Besides, the FET-type sensors can be applied to other types of sensing (for example, fine particle sensing, heavy metal sensing, and the like).

US Patent Application Publication No. US 2006/0187279 A1(Patent Document 1) discloses a gas sensor array where resistance-type gas sensors having a semi conductive metal oxide as a sensing material are arranged at a constant interval. Each gas sensor is provided with a micro-heater that can control an ambient temperature during gas sensing and a temperature sensor that can sense the ambient temperature. However, the gas sensors constituting the gas sensor array are of a resistance-type, and the distance between the gas sensors is considerably large, so that the total area is large.

In addition, since the gas sensor has a relatively large resistance-type structure, power consumption is increased to heat, a sensing material layer of the gas sensor.

Korean Patent Laid-Open Publication No. 2013-0052528 (Patent Document 2) illustrates a basic structure and advantages of an FET-type gas sensor constituting a gas sensor array proposed by the invention. The FET-type gas sensor disclosed in Patent Document 2 has a basic structure where a control electrode and a floating electrode are formed in a horizontal direction, a sensing material layer is located therebetween, and a micro-heater and an air layer are arranged near the control electrode. On the basis of the structure, the FET-type gas sensor uses a change in work function, a change in capacitance according to a change in dielectric constant, charge generation/extinction, electromotive force generation, and the like as sensing mechanisms.

The FET-type gas sensor disclosed in Patent Document 2 can significantly reduce power consumption in comparison with sensors in the related art and can sense various types of gases accurately by changing the sensing mechanisms even if the same gas sensing material is used. In addition, since the sensing material is formed in the final stage of device fabrication, there is no problem in that contamination problems occur. In the FET-type gas sensor having the above-mentioned structure disclosed in Patent Document 2, it is possible to solve the problems of the FET-type gas sensor having the floating electrode and the control electrode and the sensing material layer formed in the vertical direction in the related art. Namely, it is possible to solve the problems such as a low coupling ratio between a control electrode and a floating electrode due to a parasitic capacitance component, low sensing sensitivity, and large power consumption, and high manufacturing cost caused from complexity of processes.

However, in the above-mentioned patents, the structures and the expected effect of the arrangement, of the gas sensors are very briefly described.

Accordingly, the present invention proposes specific and efficient arrangement of a gas sensor array including FET-type gas sensors having a horizontal floating electrode and efficient design of a micro-heater and an air layer built, in each gas sensor. The array structure according to the invent ion can significantly reduce total area and total power consumption in comparison with the gas sensor arrays in the related art.

Korean Patent Laid-Open Publication No. 2014-010633 (Patent Document 3) discloses a three-dimensional Fin-FET-type gas sensor. The three-dimensional Fin-FET-type gas sensor is formed so that a floating electrode is formed to surround a semiconductor body protruding in a FIN shape to enlarge a width of a channel to increase a drain current, so that the Fin-FET-type gas sensor has an advantage of increasing the sensitivity of the sensor.

Non-Patent Document 1 is “Micro-machined gas sensor array based on metal film micro-heater,” Yaowu Mo et al., Sensors and Actuators B: Chemical, pp. 175-181, No. 79, 2001. The gas sensor array introduced in Non-Patent Document 1 is configured with eight resistance-type gas sensors, and each gas sensor has a micro-heater in which titanium (Ti) and platinum (Pt) are deposited in this order. As a sensing material, tin oxide (SnO₂) is used, and it was found that the sensing material has a selectivity for ethanol (C₂H₅OH). Unlike the studies in the related art, an air layer for reducing loss of heat of the micro-heater is formed not from a backside of a substrate, but the air layer is formed through anisotropic silicon etching of the silicon from a top side of the substrate to improve thermal characteristics. On the other hand, since the gas sensor has a resistance-type structure, the area occupied by the sensing material layer is 50 μm×50 μm in order to solve the problem of production yield. Therefore, e power consumption of the micro-heater for heating the sensing material layer and the size of the gas sensor array including eight gas sensors are very large, 2 mm×4 mm.

Non-Patent Document 2 is “Room temperature multiplexed gas sensing using chemical-sensitive 3.5-nm-thin silicon transistors”, Hossain Mohammad Fahad et al., Science Advances, e1602557, No. 3, 2017. In Non-Patent Document 2, a gas sensor constituting a gas sensor array has an FET-type structure where a silicon substrate having a bundle of thin silicon channels is as a control electrode, and the silicon channels are doped with metal substances such as palladium (Pd), nickel (Ni), and gold (Au) to analyse sensing characteristics of various gases. In addition, micro-heaters where chrome (Cr) and gold (Au) are sequentially deposited are formed in the periphery of the gas sensors, and thus, desorption rates of gases adsorbed to the sensing material layers are improved by heating the micro-heaters. However, there is no air layer for preventing loss of heat generated by the micro-heaters, and the micro-headers occupies a large area around the gas sensors, and thus, the power consumption is unnecessarily large. In addition, the size of the gas sensor array is also very large.

Therefore, development of a newly designed gas sensor array capable of solving the problems of the gas sensor arrays in the related has been required.

SUMMARY OF THE INVENTION

The invention is proposed to solve disadvantages of a sensor-array including a plurality of resistance-type sensors or FET-type sensors in the related art such as an unnecessarily large size of the sensor array, large power consumption of micro-heaters, and high manufacturing cost caused from complexity of processes. The invention is to provide an efficient arrangement of an FET-type sensor having a horizontal floating electrode constituting a sensor array and an efficient structure of a micro-heater and an air layer.

According to an aspect of the invention, there is provided an FET-type sensor array including a plurality of FET-type sensors which are arranged at arbitrary distances from one reference point, wherein the FET-type sensor includes: a semiconductor substrate; a semiconductor body formed to protrude from the semiconductor substrate; an isolation insulating film formed on a side surface of the semiconductor body; a gate insulating film formed on the semiconductor body; a floating electrode formed on the gate insulating film and the isolation insulating film; a protective insulating film formed at least on the floating electrode; a control electrode formed to face and be horizontally separated from at least one side surface of the floating electrode; a sensing material layer arranged on the control electrode and at least horizontally opposing sidewalls of the floating electrode, the sensing material layer being arranged to the floating electrode with the protective insulating film interposed therebetween; and source/drain regions formed in the semiconductor body with the floating electrode interposed therebetween, and wherein the same areas of the FET-type sensors are arranged to face a reference point.

In the FET-type sensor array according to the above aspect, the sensing material layers of a plurality of the FET-type sensors may be made of a plurality of sensing materials having different compositions, and each sensing material may be applied to one or two or more FET-type sensors.

In the FET-type sensor array according to the above aspect, the control electrode may be formed on the isolation insulating film to have a specific length and be used as a micro-heater, the protective insulating film may be formed at least on the floating electrode and the control electrode, and the FET-type sensor may further include an air layer formed at least below the isolation insulating film that is in contact with the control electrode.

In the FET-type sensor array according to the above aspects, the control electrodes used as the micro-heaters of a plurality of the FET-type sensors may be arranged to be adjacent to each other, and thus, the sensing material layer in each FET-type sensor is heated by the control electrode of each FET-type sensor and the control electrode of the adjacent FET-type sensor, or the control electrode used as the micro-heater of each FET-type sensor is formed to face a reference point, so that power consumption is reduced.

In the FET-type sensor array according to the above aspect, the control electrodes of a plurality of the FET-type sensors may be connected to each other in series or in parallel, or some of the control electrodes may be connected to each other in series and the others of the control electrodes are connected to each other in parallel; and line widths of the control electrodes used as the micro-heaters may be equal to each other or the line width may be changed depending on each FET-type sensor.

In the FET-type sensor array according to the above aspect, the line widths of the sensing material layers and the control electrodes in the peripheries thereof in the sensor array are formed to be smaller than the line widths of the control electrodes in the remaining areas, and the FET-type sensor may further include metal wires which are in electric contact with the control electrodes and a plurality of contact holes which are formed between the control electrodes and the metal wires.

In the FET-type sensor array according to the above aspect, the FET-type sensor may further include an undercut pattern for forming the air layer, and the undercut pattern may be formed to have one of shapes including a circle, an ellipse, a square, a square having rounded corners, a rectangle, a rectangle having rounded corners or maybe formed to have one of shapes including an ellipse, a rectangle, and a rectangle having rounded corners and include one or two regions that are bent at arbitrary angles in the middle.

The sensor array according to the invention basically includes a plurality of FET-type sensors having a floating electrode formed in an upper portion of a semiconductor body in which a channel is formed and a sensing material layer and a control electrode arranged in a horizontal direction thereof. At this time, the semiconductor body is formed to protrude from the semiconductor substrate, and an isolation insulating film is formed on a side surface of the semiconductor body. A micro-heater isolated by an isolation insulating film may be included in the periphery of the control electrode and the sensing material layer of the FET-type sensor, and Anisotropic etching of the Isolation insulating film and isotropic etching of the semiconductor substrate may be sequentially performed to provide an air layer below the micro-heater.

The FET-type sensors constituting the sensor array according to the invention has micro-heaters made of a metal or polycrystalline silicon having high thermal conductivity and high electric conductivity in the periphery of the control electrode and the sensing material layer. In this case, the micro-heater is arranged in the horizontal direction with respect to the floating electrode, and in the case where the micro-heater and the floating electrode are formed with the same material, the micro-heater can be formed without additional mask and process.

In the FET-type sensor constituting the sensor array according to the invention, after forming the control electrode, the isolation insulating film and the semiconductor substrate in the periphery of the sensing material layer are etched by additionally using a mask to form an air layer below the micro-heater. At this time, the air layer may be locally formed only in the periphery of the sensing material layer, so that, it is possible to minimize loss of heat of the micro-heater and to reduce power consumption.

The sensor array according to the invention may have independent micro-heaters or micro-heaters connected as a single micro-heater. When the micro-heaters are arranged in a plurality of the sensors in the sensor array, the micro-heaters of the sensors are arranged to be close to each other, and thus, it is possible to provide a structure that can be sufficiently heated by the micro-heaters of the adjacent sensors as well as the micro-heaters built in the sensors, so that it is possible to obtain the effect of reducing power consumption.

The line widths of the micro-heaters built in the FET-type sensors constituting the sensor array according to the invention can be arbitrarily adjusted. Since the maximum sensitivity of a sensing material applied to a sensor may be different depending on a heater temperature, by selecting the line width of the micro-heater suitable for the optimum temperature of reaction of each sensing material, it is possible to increase the sensitivity and to reduce power consumption.

In the FET-type sensors constituting the sensor array according to the invention, the line widths of the micro-heaters arranged in the regions other than the sensing material layers and the peripheries thereof are increased, so that it is possible to minimize the heat generation, and air layers are formed, so that it is possible to reduce loss of heat and power consumption.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exemplary equivalent circuit diagram illustrating a sensor array where a plurality of FET-type sensors are arranged in rows and columns as an example of a sensor array in the related art;

FIGS. 2A to 2D illustrate an FET-type sensor having a horizontal floating electrode in the related art, FIG. 2A is a plan view, FIG. 2B is across-sectional view taken along line A-A′ in FIG. 2A, FIG. 2C is a cross-sectional view taken along line B-B′, and FIG. 2D is a cross-sectional view of a three-dimensional Fin-FET-type sensor as a modified form of FIG. 2B;

FIG. 3 is an exemplary equivalent circuit diagram illustrating a sensor array where a plurality of FET-type sensors including a micro-heater and an air layer are arranged in rows and columns as an example of a sensor array in the related art;

FIGS. 4A to 4D illustrate an FET-type sensor in the related art as a modified form of the sensor illustrated in FIG. 2A, FIG. 4A is a plan view, FIG. 4B is across-sectional view taken along line A-A′ in FIG. 4A, FIG. 4C is a cross-sectional view taken along line B-B′, and FIG. 4D is a cross-sectional view of a three-dimensional Fin-PET-type sensor as a modified form of FIG. 4B;

FIGS. 5A to 5D illustrate examples of a sensor arrangement method of the sensor array according to the invention, FIG. 5A is an equivalent circuit diagram illustrating a case where sensors are arranged on a circle to be separated from each other at an arbitrary angle, FIG. 5B is an equivalent circuit diagram illustrating a case where sensors are arranged on an ellipse, FIG. 5C is an equivalent circuit diagram illustrating a case where sensors are arranged on a rectangle, and FIG. 5D is an equivalent circuit diagram illustrating a case where the same areas of the FET-type sensors arranged on a rectangle face a reference point and are deviated by arbitrary angles from lines connecting the reference point and the centers of the FET-type sensors;

FIGS. 6A to 6G illustrate examples of a sensor arrangement method of the sensor array according to the invention, FIG. 6A is an equivalent circuit diagram illustrating a case where sensors having a built-in micro-heater are arranged on a circle to be separated from each other at an arbitrary angle, FIG. 6B is an equivalent circuit diagram illustrating a case where sensors having a built-in micro-heater are arranged on an ellipse and the heaters are connected in series, FIG. 6C is an equivalent circuit diagram illustrating a case where sensors having a built-in micro-heater are arranged on an ellipse and the heaters are arranged in parallel, FIG. 6D is an equivalent circuit diagram illustrating a case where sensors having a built-in micro-heater are arranged on a rectangle and the heaters are connected in series, FIG. 6E is an equivalent circuit diagram illustrating a case where sensors having a built-in micro-heater are arranged on a rectangle and the heaters are arranged in parallel, FIG. 6F is an equivalent circuit diagram illustrating a case where sensors having a built-in micro-heater are arranged on a rectangle, the heaters are connected in series, and the heaters face a reference point and are deviated by arbitrary angles from lines connecting the reference point and the centers of the FET-type sensors, and FIG. 6G is an equivalent circuit diagram illustrating a case where sensors having a built-in micro-heater are arranged on a rectangle, the heaters are connected in parallel, and the heaters face a reference point and are deviated by arbitrary angles from lines connecting the reference point and the centers of the FET-type sensors;

FIGS. 7A and 7B illustrate FET-type sensors having a horizontal floating electrode in the related art constituting a sensor array according to the invention, FIG. 7A is a plan view illustrating a case where a source electrode and one-end electrode of a micro-heater are separated, and FIG. 7B is a plan view illustrating a case where a source electrode and one-end electrode of a micro-heater are shared;

FIGS., 8A and 8B illustrate modified examples of the sensors illustrated in FIGS. 7A and 7B, respectively, and are plan views illustrating cases where line widths of the micro-heaters arranged in the regions other than the sensing material layers and the peripheries thereof are increased;

FIGS. 9A and 9B illustrate modified examples of the sensors illustrated, in FIGS. 8A and 8B, respectively, and are plan views illustrating cases where the number of contact holes of the micro-heater is increased;

FIGS. 10A and 10B illustrate modified examples of the sensors illustrated in FIGS. 9A and 9B, respectively, and are plan views illustrating cases where materials having a thermal conductivity lower than that of a metal are connected to have a certain length through contact holes provided at both ends of a control electrode which is made of a metal and metal wires are connected through contact holes provided at both ends of each material having low thermal conductivity;

FIGS. 11A and 11B illustrate modified examples of the sensors illustrated in FIGS. 10A and 10B, respectively, and are plan views illustrating cases where undercut patterns are formed as close as possible to a micro-heater and anchors are formed between the patterns; and

FIGS. 12A and 12B illustrate examples of a sensor arrangement method of a sensor array according to the invention having a structure in which sensors are arranged as close as possible so as to be sufficiently heated by the micro-heaters of the adjacent sensors, FIG. 12A is a plan view illustrating a case where the sensor array is configured with sensors having the same sensing material and micro-heaters having the same line width, and FIG. 12B is a plan view illustrating a case where the sensor array is configured with sensors having different sensing materials and micro-heaters having different line widths.

DETAILED DESCRIPTION OF THE INVENTION

As illustrated in FIG. 1, unlike the related art. where sensors are arranged in arbitrary intervals of rows or/and columns, a sensor array according to a first embodiment of the invention is configured to include a plurality of FET-type sensors SO arranged at arbitrary distances from one reference point, and the same area 630 (for

example, a control electrode) of each FET-type sensor 80 is formed to face the reference point. The same area may be a control electrode or may be a control electrode that can be used as a micro-heater.

The FET-type sensor SO is an FET-type sensor 80 having a horizontal floating electrode 300 disclosed in Patent Documents 2 and 3. The FET-type sensors 80 include sensors illustrated in FIGS. 2A to 2D where a change in dielectric constant of a sensing material layer 40 according to presence or absence of a to-be-sensed material is used as an operation sensing mechanism or a change in work function is used as an operation sensing mechanism.

In particular FIG. 2D illustrates a structure of a three-dimensional Fin-FET-type sensor disclosed in Patent Document 3. The three-dimensional Fin-FET-type sensor is configured to include a semiconductor substrate 100, a semiconductor body 110 formed to protrude from the semiconductor substrate 100, an isolation insulating film 200 formed on a side surface of the semiconductor body 110 and the semiconductor substrate 100, a gate insulating film 210 formed on the semiconductor body 110, a floating electrode 300 formed on the gate insulating film 210 and the isolation insulating film 200, a control electrode 310 formed on the isolation insulating film 200 to face and be horizontally separated from at least one side surface of the floating electrode 300, a sensing material layer 40 formed between the control elect rode 310 and the floating electrode 300, and source/drain regions formed in the semiconductor body 110 with the floating gate 300 interposed therebetween, wherein the isolation insulating film 200 is formed on a lower side surface of the semiconductor body 110 such that the semiconductor body 110 protrudes, and the floating elect rode 300 is formed, to surround, the semiconductor body 110 protruding on the isolation insulating film 200 with the gate insulating film 210 interposed therebetween. The floating electrode 300 is formed to surround the semiconductor body 110 protruding in a FIN shape, and thus, the width of the channel is increased, so that a drain current is increased. Therefore, it is possible to improve the sensitivity of the sensor.

In the FET-type sensors 80, in the case where the cross-sectional structures (the cross-sectional structures taken along line A-A′) of the FET-type sensors 80 are different even though the same material is used to form the sensing material layers 40, the operation sensing mechanisms are different, and thus, the sensing materials may be different. On the contrary, in the case where the sensing material layers 40 of the FET-type sensors are different even though the cross-sectional structures of the FET-type sensors 80 are the same, the operation sensing mechanisms are different, and thus, the sensing materials may be different.

The FET-type sensor array according to the first embodiment of the invention includes two or more FET-type sensors SO having a change in capacitance caused from a change in dielectric constant or a change in work function as a operation sensing mechanism and having at least one or more sensing materials.

Even in the case where the sensing mechanisms are applied to the same sensing material layer 40, the sensing mechanisms may has different sensing characteristics (referred to as sensing fingerprints) for a specific material to be sensed. Therefore, without using a large number of sensing materials, it is possible to accurately sense the types and the concentrations of materials to be sensed.

In the FET-type sensor array according to the first embodiment of the invention, one or more sensors which are at least one or more of resistance-type and capacitance-type sensors may be arranged to be adjacent to the FET-type sensor 80,

As illustrated in FIG. 3, unlike the related art where sensors having a built-in micro-heater are arranged in arbitrary intervals of rows or/and columns, a sensor array according to a second embodiment of the invention is configured to include a plurality of FET-type sensors 80 having a horizontal floating electrode 300, a built-in heater 500, and an air layer 600 formed in a semiconductor substrate ICQ at the lower end of an isolation insulating film 200 in a region including a sensing material layer 40, the FET-type sensors are arranged at arbitrary distances from one reference point, and the same areas 630 (for example, control electrodes) of the FET-type sensors 80 are formed to face the reference point. The same area may be a control elect rode or may be a control electrode that can be used as a micro-heater.

The FET-type sensors 80 constituting the sensor array according to the embodiment include the FET-type sensors 80 disclosed in Patent Documents 2 and 3. In particular, as illustrated in FIGS. 4A to 4D, the FET-type sensors include a sensor having a micro-heater 50 and an air layer 600 having a change in dielectric constant of a sensing material layer 40 according to presence or absence of a to-be-sensed material as a operation sensing mechanism. Besides, the FET-type sensors include a sensor having a change in work function as a operation sensing mechanism. In the sensor having the operation sensing mechanism, a micro-heater 50 may be operated in common with the control electrode 310 or operated separately from the control electrode 310.

In particular, FIG. 4D illustrates a structure of a three-dimensional Fin-FET-type sensor disclosed in Patent Document 3. As described, in the first embodiment, a floating electrode 300 is formed to surround a semiconductor body 110 protruding in a FIN shape to enlarge a width of a channel to increase a drain current, so that the Fin-FET-type gas sensor has an advantage of increasing the sensitivity of the sensor.

In the FET-type sensors 80, in the case where the cross-sectional structures (the cross-sectional structures taken along line A-A′) of the FET-type sensors 80 are different even though the same material is used to form the sensing material layers 40, the operation sensing mechanisms are different, and thus, the sensing materials may be different. On the contrary, in the case where the sensing material layers 40 of the FET-type sensors are different even though the cross-sectional structures of the FET-type sensors 80 are the same, the operation sensing mechanisms are different, and thus, the sensing materials may be different.

The FET-type sensor array according to the second embodiment of the invention includes two or more FET-type sensors 80 having a change in capacitance caused from a change in dielectric constant or a change in work function as an operation sensing mechanism and having at least one or more sensing materials.

Even in the case where the sensing mechanisms are applied to the same sensing material layer 40, the sensing mechanisms may has different sensing characteristics (referred to as sensing fingerprints) for a specific material to be sensed. Therefore, without using a large number of sensing materials, it is possible to accurately sense the types and the concentrations of materials to be sensed.

In the FET-type sensor array according to the second embodiment of the invention, one or more sensors which are at least one or more of resistance-type and capacitance-type sensors may be arranged to be adjacent to the FET-type sensor 80. The resistance-type or capacitance-type sensor in the related art includes a micro-heater 50 separated by an insulating film 200 at the lower end thereof and an air layer 600 formed in a semiconductor substrate 100 at the lower end of an isolation insulating film 200 to surround the sensing material layer 40.

A sensor array according to a third embodiment of the invention is an example of the sensor array according to the first embodiment of the invention. As illustrated in FIG. 5A, a plurality of the FET-type sensors 80 are arranged in a shape of a circle having a certain radius from the reference point, and the same areas 630 of the FET-type sensors 80 are arranged to face the reference point.

A sensor array according to a fourth embodiment of the invention is an example of the sensor array according to the first embodiment of the invention. As illustrated in FIG. 5B, a plurality of the FET-type sensors 80 are arranged in a shape of an ellipse, and the same areas 630 of the FET-type sensors 80 are arranged to face the reference point.

A sensor array according to a fifth embodiment of the invention is an example of the sensor array according to the first embodiment of the invention.

As illustrated in FIG. 5C, a plurality of the FET-type sensors 80 are arranged in a rectangular shape, and the same areas 630 of the FET-type sensors 80 are arranged to face the reference point.

A sensor array according to a sixth embodiment of the invention is an example of the sensor array according to the first embodiment of the invention. As illustrated in FIG. 5D, a plurality of the FIT-type sensors 80 are arranged in a rectangular shape. The same areas 630 of the FET-type sensors 80 are arranged to face the reference point and to be deviated by arbitrary angles from lines connecting the reference point and the centers of the FET-type sensors 80. The angle θ between the line connecting the reference point and the center of the FET-type sensor 80 and the line connecting the center of the same area 630 and the center of the FET-type sensor 80 satisfies 0°=<θ<90°.

A sensor array according to a seventh embodiment of the invention is an example of the sensor array according to the second embodiment of the invention. As illustrated in FIG. 6A, a plurality of the FET-type sensors 80 are arranged in a shape of a circle having a certain radius from the reference point, and the micro-heaters 50 of the FET-type sensors 80 are arranged to face the reference point.

A sensor array according to an eighth embodiment of the invention is an example of the sensor array according to the second embodiment of the invention. As illustrated in FIGS. 6B and 6G, a plurality of the FET-type sensors 80 are arranged in a shape of an ellipse, and the micro-heaters 50 of the FET-type sensors 80 are arranged to face the reference point. FIG. 6B illustrates an example where the micro-heaters 50 are connected in series, one terminal of each micro-heaters 50 is applied with a heater voltage V_H, and the other terminal thereof is connected to the ground. FIG. 6C illustrates an example where the micro-heaters 50 are connected in parallel, one terminal of each micro-heaters 50 is applied with a heater voltage the other terminal thereof is connected to the ground, and the ground terminals of the micro-heaters 50 are shared as one,

A sensor array according to a ninth embodiment of the invention is an example of the sensor array according to the second embodiment of the invention. As illustrated in FIGS. 6D and 6E, a plurality of the FET-type sensors are arranged in a shape of a rectangle, and the micro-heaters 50 of the FET-type sensors 80 are arranged to face the reference point. FIG. 6D illustrates an example where the micro-heaters 50 are connected in series, one terminal of each micro-heaters 50 is applied with a heater voltage V_H, and the other terminal thereof is connected to the ground, FIG. 6E illustrates an example where the micro-heaters 50 are connected in parallel, one terminal of each micro-heaters 50 is applied with a heater voltage V_H, the other terminal thereof is connected to the ground, and the ground terminals of the micro-heaters 50 are shared as one.

A sensor array according to a tenth embodiment of the invention is an example of the sensor array according to the second embodiment of the invention. As illustrated in FIGS. 6F and 6G, a plurality of the FET-type sensors 80 are arranged in a rectangular shape, the micro-heaters 50 of the FET-type sensors 80 are arranged to face the reference point and to be deviated by arbitrary angles from lines connecting the reference point and the centers of the FET-type sensors 80. The angle θ between the line connecting the reference point and the center of the FET-type sensor 80 and the line connecting the center of the micro-heater 50 and the center of the FET-type sensor 80 satisfies 0°=<θ<90°. FIG. 6F illustrates an example where the micro-heaters 50 are connected in series, one terminal of each micro-heaters 50 is applied with a heater voltage V_H, and the other terminal thereof is connected to the ground. FIG. 6G illustrates an example where the micro-heaters 50 are connected in parallel, one terminal of each micro-heaters 50 is applied with a heater voltage V_H, the other terminal thereof is connected to the ground, and the ground terminals of the micro-beaters 50 are shared as one.

In the sensor arrangement method of the sensor arrays according to the first to tenth embodiments, in comparison with the sensor array including sensors having micro-heaters in the related art where the sensors are arranged in rows or/and columns, the total area occupied by the sensor array is small, and the micro-heaters 50 built in the sensors are arranged to be close to each other, and thus, the sensing material layers 40 can be heated by the adjacent micro-heaters 50. Therefore, there is an advantage in that the total power consumption can also be reduced.

In the sensor arrays according to the first to sixth embodiments, the control electrode 310, the micro-heater 50, the source/drain electrode 320, the active region 120, and other regions constituting the FET-type sensor 80 are included in the same area 630 of the FET-type sensor 80.

A sensor has the optimum temperature at which the sensitivity of the sensor is maximized for each sensing material and each material to be sensed. Therefore, in the case where two or more different sensing materials are applied to each of the sensor arrays according to the second and seventh to tenth embodiments, the line widths of the micro-heaters 50 built in the sensors may be designed differently according to the optimum temperatures of reaction of the sensing materials, so that the resistance can be different.

In the sensor arrays according to the second and seventh to tenth embodiments illustrated in FIGS. 6A to 6G, combinations of the resistance values R₁ to R_n of the micro-heaters 50 are available as follows. All the resistance values are equal to each other (R₁=R₂=R₃=. . . R_n) all the resistance values are different from each other (R₁≠R₂≠R₃≠. . . R_n); and some of the resistance values are equal to each other and the others are different from each other (R₁=R₂=. . . R_n-1≠R_n, R₁=R₂=R_n-2≠R_n-1R_n).

In the sensor arrays according to the second and seventh to tenth embodiments, all the micro-heaters 50 built in a plurality of the sensors may be connected in series or in parallel, or an arbitrary number of some of the micro-heaters 50 built in a plurality of the sensors may be connected in series or in parallel.

In the sensor arrays according to the second and seventh to tenth embodiments, in the FET-type sensor including the micro-heater 50 operated separately from the control electrode 310, the source electrode 320 of the FET-type sensor the one end of the micro-heater 50 built in each FET-type sensor may be separated as illustrated in FIG. 7A or may be shared with one common electrode 330 as illustrated in FIG. 7B.

As illustrated in FIGS. 8A and 8B, in the sensor arrays according to the second and seventh to tenth embodiments, the line widths of the sensing material layers 40 of FET-type sensors and the line widths of the micro-heaters 50 in the peripheries of the sensing material layers 40 are configured to be larger than the line widths of the micro-heaters 50 arranged in the regions other than the sensing material layers 40 and the peripheries of the sensing material layers 40, and thus, the heat generated is reduced, so that it is possible to reduce loss of heat.

As illustrated in FIGS. 9A and 9B, in the sensor arrays according to the second and seventh to tenth embodiments, in order to prevent the micro-heaters 50 from being physically disconnected and destructed by the heat generated from the contact holes 70 for electrically connecting the micro-heaters 50 and the metal wires 311, the number of contact holes 70 is configured to be sufficiently large, and thus, the total contact area is increased, so that it is possible to improve the mechanical stability.

As illustrated in FIGS. 10A and 10B, in the sensor arrays according to the second and seventh to tenth embodiments, in the case where the control electrode 310 is a metal, the material 90 having a thermal conductivity lower than that of the metal is connected to a region of the control electrode 310 through the contact hole 70 and arranged with a predetermined length, and the metal wire 311 is connected through the contact hole 70 provided at the end of the material 90 having low thermal conductivity. As the material 90 having a thermal conductivity lower than that of the metal, there may be exemplified polysilicon. The material 90 having low thermal conductivity is additionally arranged between, the control electrode 310 made of a metal and the metal wire 311, so that there is an advantage in that loss of heat generated from the micro-heaters 50 through the metal wire 311 can be reduced.

In this case, since the two connection portions are electrically connected through the contact hole 70, there is no problem in gating the control electrode 310 for the operation of the sensor.

In the sensor arrays according to the second and seventh to tenth embodiments, the region of the air layer 600 functioning to reduce the loss of heat of the micro-heater 50 built in each FET-type sensor always includes the sensing material layer 40. The formation process for the air layer 600 is performed by anisotropically etching the isolation insulating film 200 below the undercut pattern 610 by dry etching or wet etching using a gas such as CF₄, and subsequently by isotropically etching the semiconductor substrate 100 below the isolation insulating film 200 by dry etching or wet etching using a gas such as SF₆.

The undercut pattern 610 is an open pattern and may be formed by selecting one of shapes including a circular, an ellipse, a square, a square having rounded corners, a rectangle, a rectangle having rounded corners or may be formed by selecting one of shapes including an ellipse, a rectangle, and a rectangle having rounded corners and including at least one region that is bent at an arbitrary angle in the middle. In particular, as illustrated in FIGS. 11A and 11B, the width of the undercut pattern 610 is configured to be sufficiently thin so that, when the sensing material layer 40 is formed by a method such as Inkjet printing, the amount of sensing material that is lost through the air layer 600 is reduced and the sensing material is well deposited between the floating electrode 300 and the floating electrode 300. Namely, it is possible to obtain the effect of increasing the sensor production yield. The undercut pattern 610 is designed to be arranged as close as possible to the micro-heater 50, so that the active region 120 of the sensor is not damaged while the semiconductor substrate 100 is etched to form, the air layer 600. Therefore, it is possible to obtain the effect, of ensuring mechanical stability. Finally, an anchor 620 between the undercut pattern 610 and another adjacent, pattern, is allowed to remain, so that the sensor can be prevented from collapsing toward the semiconductor substrate 100 after the etching of the air layer 600.

As illustrated in FIGS. 11A and 11B, the undercut patterns 610 are formed in the peripheries of the control, electrodes 310 arranged in the regions other than the sensing material layers 40 and the peripheries thereof, between the floating electrode 300 and the active region 120, and in the peripheries of the portions where the micro-heaters 50 and the metal wires 311 are connected to the contact holes 70, and thus the loss of heat of the micro-heater 50 is minimized.

As illustrated in FIGS. 12A and 12B, in the sensor array according to the fifth embodiment of the invention, two sensors of the sensor array according to the second embodiment are included, the two sensors are formed as close as possible, and the undercut pattern 610 and the anchor 620 for mechanical stability of the sensor array are included between the two sensors, FIG. 12A illustrates the sensor array to which the same sensing material is applied, and the micro-heaters 50 have the same line width. FIG. 12B illustrates the sensor array to which different sensing materials are applied, and the micro-heaters 50 have different line widths.

As illustrated in FIGS. 5A to 11B, other features of the sensor array according to the fifth embodiment include all the features described in the second and seventh to tenth embodiments.

A sensor array according to the invention can be implemented by simple processes and can be easily combined with existing CMOS processes, so that industrial applicability is high.

In particular, the sensor array according to the invention has a higher degree of integration than that of a sensor array developed in the related art, production yield is high, manufacturing cost is low, the sensor array can be driven with low power, and the sensor array can be usefully applied for various sensor fields of gas sensors, chemical and biological sensors, and the like.

While the: present invention has been particularly illustrated, and described, with reference to exemplary embodiments thereof, it should be understood by the skilled in the art that the invention is not limited to the disclosed embodiments, but various modifications and applications not illustrated in the above description can be made without departing from the spirit of the invention. In addition, differences relating to the modifications and applications should be construed as being included within the scope of the invention as set forth in the appended claims.

Claims

1. An FET-type sensor array comprising;

a plurality of FET-type sensors which are arranged at arbitrary distances from one reference point,

wherein the FET-type sensor includes: a semiconductor substrate; a semiconductor body formed to protrude from the semiconductor substrate;

an isolation insulating film formed on a side surface of the semiconductor body;

a gate insulating film formed on the semiconductor body;

a floating electrode formed on the gate insulating film and the isolation insulating film;

a protective insulating film formed at least on the floating electrode;

a control electrode formed to face and be horizontally separated from at least one side surface of the floating electrode;

a sensing material layer arranged on the control electrode and at least horizontally opposing sidewalls of the floating electrode, the sensing material layer being arranged to the floating electrode with the protective insulating film interposed therebetween; and

source/drain regions formed in the semiconductor body with the floating electrode interposed therebetween, and

wherein the same areas of the FET-type sensors are arranged to face a reference point.

2. The FET-type sensor array according to claim 1,

wherein the sensing material layers lot a plurality of the FET-type sensors are made of a plurality of sensing materials having different compositions, and each sensing material is applied to one or more FET-type sensors.

3. The FET-type sensor array according to claim 1,

wherein the control electrode is formed on the isolation insulating film to have a specific length and is used as a micro-heater,

wherein the protective insulating film is formed at least on the floating electrode and the control electrode, and

wherein the FET-type sensor further includes an air layer formed at least below the isolation insulating film that is in contact with the control electrode.

4. The FET-type sensor array according to claim 3, wherein the sensing material layers of a plurality of the FET-type sensors are made of a plurality of sensing materials having different compositions, and each sensing material is applied to one or more FET-type sensors,

5. The FET-type sensor array according to claim 3, wherein the control electrodes used as the micro-heaters of a plurality of the FET-type sensors are arranged to be adjacent to each other, and thus, the sensing material layer in each FET-type sensor is heated by the control electrode of each FET-type sensor and the control electrode of the adjacent FET-type sensor, or the control electrode used as the micro-heater of each FET-type sensor is formed to face a reference point, so that power consumption is reduced.

6. The FET-type sensor array according to claim 3,

wherein the control electrodes of a plurality of the FET-type sensors are connected to each other in series or in parallel, or some of the control electrodes are connected to each other in series and the others of the control electrodes are connected to each other in parallel, and

wherein line widths of the control electrodes used as the micro-heaters are equal to each ether or the line width is changed depending on each FET-type sensor.

7. The FET-type sensor array according to claim 3,

wherein the FET-type sensor further includes: metal wires which are in electric contact with the control electrodes; and a plurality of contact holes which are formed between the control electrodes and the metal wires, and

wherein the line widths of the sensing material layers and the control electrodes in the peripheries thereof in the sensor array are formed to be smaller than the line widths of the control electrodes in the remaining areas.

8. The FET-type sensor array according to claim 3,

wherein the FET-type sensor further includes an undercut pattern for forming an air layer, and

wherein the undercut pattern is formed to have one of shapes including a circle, an ellipse, a square, a square having rounded corners, a rectangle, a rectangle having rounded corners or formed to have one of shapes including an ellipse, a rectangle, and a rectangle having rounded corners and include one or more regions that are bent at arbitrary angles in the middle.

9. The FET-type sensor array according to claim 1,

wherein the control electrode is formed to have a specific length is used as a micro-heater, and

wherein the FET-type sensor further includes an air layer formed at least below art isolation insulating film which is in contact, with the control electrode.

10. The FET-type sensor array according to claim 9, wherein the sensing material layers of a plurality of the FET-type sensors are made of a plurality of sensing materials having different compositions, and each sensing material is applied to one or more FET-type sensors.

11. The FET-type sensor array according to claim 9, wherein the control electrodes used as the micro-heaters of a plurality of the FET-type sensors are arranged to be adjacent to each other, and thus, the sensing material layer in each FET-type sensor is heated by the control electrode of each FET-type sensor and the control electrode of the adjacent FET-type sensor, or the control electrode used as the micro-heater of each FET-type sensor is formed to face a reference point, so that power consumption is reduced.

12. The FET-type sensor array according to claim 9,

wherein the control electrodes of a plurality of the FET-type sensors are connected to each other in series or in parallel, or some of the control electrodes are connected to each other in series and the others of the control electrodes are connected to each other in parallel, and

where line widths of the control electrodes used as the micro-heaters are equal to each other or the line width is changed depending on each FET-type sensor.

13. The FET-type sensor array according to claim 9,

wherein the FET-type sensor includes: metal, wires which are in electric contact with the control electrodes; and a plurality of contact holes which are formed between the control electrodes and the metal wires,

wherein the line widths of the sensing material layers and the control electrodes in the peripheries thereof in the sensor array are formed to be smaller than the line widths of the control electrodes in the remaining areas, and

wherein, in the case where the control electrode that is in contact with the sensing material layer is made of metal, a material having a thermal conductivity lower than that of a metal is connected through contact holes provided at both ends of the control electrode and arranged with a predetermined length, and a metal wire is connected through contact holes provided at both ends of the material having low thermal conductivity.

14. The FET-type sensor array according to claim 9,

wherein the FET-type sensor further includes an undercut pattern for forming an air layer, and

wherein the undercut pattern is formed to have one of shapes including a circle, an ellipse, a square, a square having rounded corners, a rectangle, a rectangle having rounded corners or formed to have one of shapes including an ellipse, a rectangle, and a rectangle having rounded corners and include one or two regions that are bent at arbitrary angles in the middle.

15. The FET-type sensor array according to claim 1,

wherein the FET-type sensor further includes: a micro-heater formed with a predetermined length on the isolation insulating film to face and be horizontally separated from at least one side surface of the floating electrode; and an air layer formed at least below the isolation insulating film that is in contact with the micro-heater,

wherein the protective insulating film is formed at least on the floating electrode and the micro-heater, and

wherein the micro-heater of each FET-type sensor is formed to face the reference point.

16. The FET-type sensor array according to claim 15, wherein the sensing material layers of a plurality of the FET-type sensors are made of a plurality of sensing materials having different compositions, and each sensing material is applied to one or more FET-type sensors.

17. The FET-type sensor array according to claim 15, wherein the micro-heaters of a plurality of the FET-type sensors are arranged to be adjacent to each other, and thus, the sensing material layer in each FET-type sensor is heated by the micro-heater of each FET-type sensor and the micro-heater of the adjacent. PET- type sensor, so that power consumption is reduced.

18. The FET-type sensor array according to claim 15,

wherein the micro-heaters of a plurality of the FET-type sensors are connected to each other in series or in parallel, or some of the micro-healers are connected to each other in series and the others of the micro-heaters are connected to each other in parallel, and

wherein the line widths of the micro-heaters are equal to each other or the line width is changed depending on each FET-type sensor.

19. The FET-type sensor array according to claim 15,

wherein the FET-type sensor further includes: a metal wire which, is in electric contact with the micro-heater; and a plurality of contact holes which are formed between, the micro-heater and the metal wire,

wherein the line widths of the sensing material layers and the micro-heaters in the peripheries thereof in the sensor array are formed to he smaller than the line widths of the micro-heaters in the remaining areas, and

wherein, in the case where the control electrode that is in contact with the sensing material layer is made of metal, a material having a thermal conductivity lower than that of a metal is connected through contact holes provided at both ends of the control electrode and arranged with a predetermined length, and a metal wire is connected through contact holes provided at both ends of the material having low thermal conductivity.

20. The FET-type sensor array according to claim 15,

wherein the FET-type sensor further includes an undercut pattern for forming an air layer, and

wherein the undercut pattern is formed to have one of shapes including a circle, an ellipse, a square, a square having rounded corners, a rectangle, a rectangle having rounded corners or formed to have one of shapes including an ellipse, a rectangle, and a rectangle having rounded corners and include one or more regions that are bent at arbitrary angles in the middle.