Abstract: Described herein is a technique capable of reducing a thermal damage to a furnace opening structure when processing a substrate at a high temperature. According to one aspect thereof, there is provided a substrate processing apparatus including: a reaction tube provided with a furnace opening; heaters provided respectively in a plurality of zones arranged along a tube axis direction; temperature sensors respectively corresponding to the zones; a temperature controller configured to control electric power based on temperature data obtained by the temperature sensors, wherein the temperature controller is configured to, when the substrates are subject to a heat treatment process by the heaters, control the electric power supplied to the heaters such that temperatures of upper heaters about as high as the substrates reach predetermined temperatures, and that a temperature gradient is formed in lower zones lower than the substrates such that a temperature decreases toward the furnace opening.

Abstract: A method for manufacturing a semiconductor structure and the semiconductor structure are provided. The method includes the following operations. A substrate provided with a plurality of active areas arranged at intervals is provided. A first laminated structure and a first photoresist layer are sequentially formed on the substrate. Negative Type Develop (NTD) is performed on the first photoresist layer, to form a first pattern. The first laminated structure is etched along the first pattern, to form a second pattern in the first laminated structure. The substrate is etched up to a preset depth by taking the first laminated structure having the second pattern as a mask, to form a recess and form a plurality of protuberances arranged at intervals on the reserved substrate. The recess surrounds the protuberance, and the active area is exposed between the protuberances.

Abstract: An improved particle beam inspection apparatus, and more particularly, a particle beam inspection apparatus including a thermal conditioning station for preconditioning a temperature of a wafer is disclosed. The charged particle beam apparatus may scan the wafer to measure one or more characteristics of the structures on the wafer and analyze the one or more characteristics. The charged particle beam apparatus may further determine a temperature characteristic of the wafer based on the analysis of the one or more characteristics of the structure and adjust the thermal conditioning station based on the temperature characteristic.

Abstract: A trench-isolated RESURF diode structure (100) is provided which includes a substrate (150) in which is formed anode (130, 132) and cathode (131) contact regions separated from one another by a shallow trench isolation region (114, 115), along with a non-uniform cathode region (104) and peripheral anode regions (106, 107) which define vertical and horizontal p-n junctions under the anode contact regions (130, 132), including a horizontal cathode/anode junction that is shielded by the heavily doped anode contact region (132).

Abstract: A semiconductor device includes a transistor, a capacitor and a resistor wherein the capacitor includes a doped polysilicon layer to function as a bottom conductive layer with a salicide block (SAB) layer as a dielectric layer covered by a Ti/TiN layer as a top conductive layer thus constituting a single polysilicon layer metal-insulator-polysilicon (MIP) structure. While the high sheet rho resistor is also formed on the same single polysilicon layer with differential doping of the polysilicon layer.

Abstract: A semiconductor structure and a manufacturing method and an operating method for the same are provided. The semiconductor structure comprises a first well region, a second well region, a first doped region, a second doped region, an anode, and a cathode. The second well region is adjacent to the first well region. The first doped region is on the second well region. The second doped region is on the first well region. The anode is coupled to the first doped region and the second well region. The cathode is coupled to the first well region and the second doped region. The first well region and the first doped region have a first conductivity type. The second well region and the second doped region have a second conductivity type opposite to the first conductivity type.

Abstract: Disclosed are embodiments of a bipolar or heterojunction bipolar transistor and a method of forming the transistor. The transistor can incorporate a dielectric layer sandwiched between an intrinsic base layer and a raised extrinsic base layer to reduce collector-base capacitance Ccb, a sidewall-defined conductive strap for an intrinsic base layer to extrinsic base layer link-up region to reduce base resistance Rb and a dielectric spacer between the extrinsic base layer and an emitter layer to reduce base-emitter Cbe capacitance. The method allows for self-aligning of the emitter to base regions and incorporates the use of a sacrificial dielectric layer, which must be thick enough to withstand etch and cleaning processes and still remain intact to function as an etch stop layer when the conductive strap is subsequently formed. A chemically enhanced high pressure, low temperature oxidation (HIPOX) process can be used to form such a sacrificial dielectric layer.

Abstract: A method far farming different active thicknesses on the same silicon layer includes masking the silicon layer and exposing selected regions of the silicon layer. The thickness of the silicon layer at the exposed regions is changed, either by adding silicon or subtracting silicon from the layer at the exposed regions. Once the mask is removed, the silicon layer has regions of different active thicknesses, respectively suitable for use in different types of devices, such as diodes and transistors.

Abstract: An optocoupler device facilitates on-chip galvanic isolation. In accordance with various example embodiments, an optocoupler circuit includes a silicon-on-insulator substrate having a silicon layer on a buried insulator layer, a silicon-based light-emitting diode (LED) having a silicon p-n junction in the silicon layer, and a silicon-based photodetector in the silicon layer. The LED and photodetector are respectively connected to galvanically isolated circuits in the silicon layer. A local oxidation of silicon (LOCOS) isolation material and the buried insulator layer galvanically isolate the first circuit from the second circuit to prevent charge carriers from moving between the first and second circuits. The LED and photodetector communicate optically to pass signals between the galvanically isolated circuits.

Abstract: A substrate may have active areas at different levels separated by a mask. Along the mask may be a shallow trench isolation. Along the shallow trench isolation may be a LOCOS isolation. The shape of a substrate transition region between the levels may be tunably controlled. The shallow trench isolation may reduce the bird's beak effect.

Abstract: Methods of fabricating an oxide layer on a semiconductor substrate are provided herein. The oxide layer may be formed over an entire structure disposed on the substrate, or selectively formed on a non-metal containing layer with little or no oxidation of an exposed metal-containing layer. The methods disclosed herein may be performed in a variety of process chambers, including but not limited to decoupled plasma oxidation chambers, rapid and/or remote plasma oxidation chambers, and/or plasma immersion ion implantation chambers. In some embodiments, a method may include providing a substrate comprising a metal-containing layer and non-metal containing layer; and forming an oxide layer on an exposed surface of the non-metal containing layer by exposing the substrate to a plasma formed from a process gas comprising a hydrogen-containing gas, an oxygen-containing gas, and at least one of a supplemental oxygen-containing gas or a nitrogen-containing gas.

Abstract: An element isolation film is formed by filling an oxide in a trench formed in an element isolation region of a semiconductor substrate to thereby form an insulation film for element isolation. A method of forming the element isolation film includes a first step of depositing a material in a plasma state including oxygen and silicon on an inner surface of the trench while applying no bias voltage (or a relatively low voltage), and a second step of filling the material in a plasma state including oxygen and silicon in the trench while applying a bias voltage (or a relatively high voltage).

Abstract: A method for forming different active thicknesses on the same silicon layer includes masking the silicon layer and exposing selected regions of the silicon layer. The thickness of the silicon layer at the exposed regions is changed, either by adding silicon or subtracting silicon from the layer at the exposed regions. Once the mask is removed, the silicon layer has regions of different active thicknesses, respectively suitable for use in different types of devices, such as diodes and transistors.

Abstract: Methods of fabricating an oxide layer on a semiconductor substrate are provided herein. The oxide layer may be formed over an entire structure disposed on the substrate, or selectively formed on a non-metal containing layer with little or no oxidation of an exposed metal-containing layer. The methods disclosed herein may be performed in a variety of process chambers, including but not limited to decoupled plasma oxidation chambers, rapid and/or remote plasma oxidation chambers, and/or plasma immersion ion implantation chambers. In some embodiments, a method may include providing a substrate comprising a metal-containing layer and non-metal containing layer; and forming an oxide layer on an exposed surface of the non-metal containing layer by exposing the substrate to a plasma formed from a process gas comprising a hydrogen-containing gas, an oxygen-containing gas, and at least one of a supplemental oxygen-containing gas or a nitrogen-containing gas.

Abstract: A method for fabricating an LCOS device. The method includes providing a semiconductor substrate and forming a plurality of MOS transistor devices formed on a portion of the semiconductor substrate. The method includes forming a first dielectric layer overlying the plurality of transistor devices and forming a first metal layer overlying the first dielectric layer. The method includes forming a second dielectric layer overlying the first metal layer and forming a plurality of pixel regions made substantially of silver bearing material overlying the second dielectric layer. In a preferred embodiment, the silver bearing material has much higher reflectivity for wavelengths of 450 nanometers and greater.

Abstract: An efficient method is disclosed for creating different field oxide profiles in a local oxidation of silicon process (LOCOS process). The method comprises (1) forming a first portion of the field oxide with a first field oxide profile (e.g., an abrupt bird's beak profile) during a field oxide oxidation process, and (2) forming a second portion of the field oxide with a second field oxide profile (e.g., a graded bird's beak profile) during the field oxide oxidation process. A graded bird's beak profile enables higher breakdown voltages. An abrupt bird's beak profile enables higher packing densities. The method gives an integrated circuit designer the flexibility to create an appropriate field oxide profile at a desired location.

Abstract: In an embodiment, a method of forming a gate structure for a semiconductor device includes forming a preliminary gate structure on a semiconductor substrate. The preliminary gate structure includes a gate oxide pattern and a conductive pattern sequentially stacked on the substrate. Then, a re-oxidation process is performed to the substrate having the preliminary gate structure using an oxygen radical including at least one oxygen atom, so that an oxide layer is formed on a surface of the substrate and sidewalls of the preliminary gate structure to form the gate structure for a semiconductor device. The thickness of the gate oxide pattern is prevented from increasing, and the quality of the oxide layer is improved.

Abstract: A method for forming different active thicknesses on the same silicon layer includes masking the silicon layer and exposing selected regions of the silicon layer. The thickness of the silicon layer at the exposed regions is changed, either by adding silicon or subtracting silicon from the layer at the exposed regions. Once the mask is removed, the silicon layer has regions of different active thicknesses, respectively suitable for use in different types of devices, such as diodes and transistors.

Abstract: Electrostatic discharge (ESD) protection is provided for an integrated circuit. Snap back from a lower initial critical voltage and critical current is provided, as compared to contemporary designs. A dynamic region having doped regions is formed on a substrate, interconnects contacting the dynamic region. The dynamic region includes an Nwell region, a Pwell region and shallow diffusions, defining a PNP region, an NPN region and a voltage Breakdown region. In an aspect, the Nwell region includes a first N+ contact, a first P+ contact and an N+ doped enhancement, while the Pwell region includes a second N+ contact, a second P+ contact and a P+ doped enhancement. The N+ doped enhancement contacts the P+ doped enhancement forming the breakdown voltage region therebetween, in one case forming a buried breakdown voltage junction.

Abstract: A temperature regulating method in a thermal processing system includes controlling a heating means by performing integral operation, differential operation and proportional operation by means of a heating control section in a manner a detection temperature by a temperature detecting means becomes a predetermined target temperature, determining a first output control pattern by patterning a first operation amount for the heating control section to control the heating means depending upon a detection temperature detected by a first temperature detecting means, in controlling the heating means controlling the heating means by means of the heating control section depending upon the first output control pattern determined, and determining a second output control pattern by patterning at least a part of a second operation amount for the heating control section to control the heating means depending upon a detection temperature detected by a second temperature detecting means, in controlling the heating means.

Abstract: The semiconductor device according to the invention includes a substrate, a field insulating region which delimits an active region of the semiconductor substrate, a collector, at least one collector contact region associated with the collector, and a base with an associated base connection region. The collector and the collector contact region are formed in the same active region. In addition the base connection region extends partially over the active region and is separated from the surface of the active region by an insulator layer.

Abstract: A method for fabricating a transistor of a semiconductor device is provided. The method includes: forming device isolation layers in a substrate including a bottom structure, thereby defining an active region; etching the active region to a predetermined depth to form a plurality of recess structures each of which has a flat bottom portion with a critical dimension (CD) larger than that of a top portion; and sequentially forming a gate oxide layer and a metal layer on the recess structures; and patterning the gate oxide layer and the metal layer to form a plurality of gate structures.

Abstract: A method for forming a high-luminescence Si electroluminescence (EL) phosphor is provided, with an EL device made from the Si phosphor. The method comprises: depositing a silicon-rich oxide (SRO) film, with Si nanocrystals, having a refractive index in the range of 1.5 to 2.1, and a porosity in the range of 5 to 20%; and, post-annealing the SRO film in an oxygen atmosphere. DC-sputtering or PECVD processes can be used to deposit the SRO film. In one aspect the method further comprises: HF buffered oxide etching (BOE) the SRO film; and, re-oxidizing the SRO film, to form a SiO2 layer around the Si nanocrystals in the SRO film. In one aspect, the SRO film is re-oxidized by annealing in an oxygen atmosphere. In this manner, a layer of SiO2 is formed around the Si nanocrystals having a thickness in the range of 1 to 5 nanometers (nm).

Abstract: A sidewall-insulation film 9 is provided on a side surface of a first opening portion 8a formed in a base extraction electrode 5B of a hetero-junction bipolar transistor, and a portion of the sidewall-insulation film 9 extends so as to protrude from a surface opposite to a semiconductor substrate 1 toward a main surface of the semiconductor substrate 1 in the base extraction electrode 5B, and protruded length thereof is set to be equal to or smaller than one half of thickness of the insulation film 4 interposed between the main surface of the semiconductor substrate 1 and a lower surface of the base extraction electrode 5B.

Abstract: Disclosed is a method of forming the floating gate in the flash memory device. After the first polysilicon film is deposited on the semiconductor substrate, the trench is formed on the first polysilicon film with the pad nitride film not deposited. The HDP oxide film is then deposited to bury the trench. Next, the HDP oxide film is etched to define a portion where the second polysilicon film will be deposited in advance. The second polysilicon film is then deposited on the entire top surface, thus forming the floating gate. Thus, it is possible to completely remove a moat and an affect on EFH (effective field oxide height), solve a wafer stress by simplified process and a nitride film, and effectively improve the coupling ratio of the flash memory device.

Abstract: The present invention discloses semiconductor device which comprises a metal gate electrode surrounded by polysilicon layers and a gate insulating film whose edges are thicker than the center portion formed according to a reoxidation process using a thermal process before the formation of an ion implantation region in a process for forming the metal gate electrode using a replacement process and method for manufacturing the same.

Abstract: A method of forming an isolation trench in a semiconductor includes forming a first isolation trench portion having a first depth and having a first sidewall intersecting a surface of the semiconductor at a first angle. The method also includes forming a second isolation trench portion within and extending below the first isolation trench portion. The second isolation trench portion has a second depth and includes a second sidewall. The second sidewall intersects the first sidewall at an angle with respect to the surface that is greater than the first angle. A dielectric material fills the first and second isolation trench portions.

Abstract: A silicon controlled rectifier for SiGe process. The silicon controlled rectifier comprises a substrate, a buried layer of a first conductivity type in the substrate, a well of the first conductivity type in the substrate and above the buried layer, a doped region of a second conductivity type in the well, a first conducting layer of the second conductivity type on the substrate, and a second conducting layer of the first conductivity type on the first conducting layer.

Abstract: A temperature control method is provided which is capable of performing quick, accurate, and error-free soaking control over all wafer areas to be thermally treated at a target temperature without requiring any skilled operator and which can be automated by using a computer. In the temperature control method of controlling a heating apparatus having at least two heating zones in such a manner that temperatures detected at predetermined locations equal a target temperature therefor, temperatures are detected at predetermined locations the number of which is larger than the number of the heating zones, and the heating apparatus is controlled in such a manner that the target temperature falls between a maximum value and a minimum value of a plurality of detected temperatures.

Abstract: According to one embodiment of the invention, a method for manufacturing bipolar junction transistors includes disposing a first oxide layer between a semiconductor substrate and a base polysilicon layer, forming a dielectric layer outwardly from the base polysilicon layer, and forming an emitter region by removing a portion of the dielectric layer and a portion of the base polysilicon layer. The method further includes removing a portion of the first oxide layer to form undercut regions adjacent the emitter region and to enlarge the emitter region, and forming an oxide pad outwardly from the semiconductor substrate in the emitter region.

Abstract: A method of forming a buried silicon oxide region in a semiconductor substrate with portions of the buried silicon oxide region formed underlying portions of a strained silicon shape, and where the strained silicon shape is used to accommodate a semiconductor device, has been developed. A first embodiment of this invention features a buried oxide region formed in a silicon alloy layer, via thermal oxidation procedures. A first portion of the strained silicon layer, protected during the thermal oxidation procedure, overlays the silicon alloy layer while a second portion of the strained silicon layer overlays the buried oxide region. A second embodiment of this invention features an isotropic dry etch procedure used to form an isotropic opening in the silicon alloy layer, with the opening laterally extending under a portion of the strained silicon layer.

Abstract: A method of forming a localized oxidation having reduced bird's beak encroachment in a semiconductor device by providing an opening in the silicon substrate that has sloped sidewalls with a taper between about 10° and about 75° as measured from the vertical axis of the recess opening and then growing field oxide within the tapered recess opening for forming the localized oxidation.

Abstract: A semiconductor device fabrication method includes the steps of forming a first insulation layer and a first semiconductor layer sequentially on a semiconductor substrate having a buried diffusion region therein. A second insulation layer is formed on the first semiconductor layer. The first insulation layer, the first semiconductor layer, and the second insulation layer are then patterned to create openings that expose the buried diffusion region. A third insulation layer is formed on respective side walls of the openings on the exposed portions of the first semiconductor layer, first insulation layer and second insulation layer that form the openings. A first epitaxial layer is formed on the semiconductor substrate exposed through the openings. A second epitaxial layer is then formed on the first epitaxial layer to be connected to the first semiconductor layer, thereby forming an active base region and a second conductive type collector region in the second epitaxial layer of the first and second openings.

Abstract: a method of semiconductor device isolation, which can minimize an design rule of trenches comprising the steps of providing a substrate where a device isolation region was defined; removing the device isolation region of the substrate using a photolithography process to form trenches; implanting ions into the substrate having the trenches to form an impurity layer having a uniform depth relative to the surface of the substrate; thermally oxidizing the substrate having the impurity layer to form an oxide film; and removing the oxide film.

Abstract: A method for monitoring bipolar junction transistor emitter window etching process is disclosed. The method at least includes the following steps. First of all, a substrate is provided having a silicon oxide layer thereon and a silicon nitride layer on the silicon oxide layer. Then, a semiconductor layer is deposited on the silicon nitride layer. Next, a conductive region of a first conductivity type is formed in the semiconductor layer. Then, a dielectric layer is formed on the semiconductor layer. Then, the dielectric layer and the semiconductor layer are anisotropically etched to stop on the silicon oxide layer to define an emitter region of the bipolar junction transistor. Finally, the silicon oxide layer is isotropically etched.

Abstract: A number of npn and pnp bipolar transistors are formed in a single chip of silicon, so that some of the transistors have a greater frequency response than others The higher frequency transistors have their emitters located closer to the collectors, by positioning a collector, or emitter, of a transistor in a recessed portion of the surface of the chip. The recess is formed in an accurate and controlled manner by locally oxidising the silicon surface, and subsequently removing the oxide to leave the recess.

Abstract: A semiconductor photomask set for producing wafer alignment accuracy in a semiconductor fabrication process. The photomask set produces an alignment mark that is accurate for subsequent fabrication after undergoing a dual field oxide (FOX) fabrication process. Prior arts methods have traditionally covered the alignment marks with layers of oxide material.

Abstract: A field-effect transistor and a method for its fabrication are described. The transistor includes a monocrystalline channel region extending from a monocrystalline body region of a semiconductor substrate. First and second source/drain regions laterally adjoin opposite sides of the channel region and are electrically isolated from the body region by an underlying first dielectric layer. The source/drain regions include both polycrystalline and monocrystalline semiconductor regions. A conductive gate electrode is formed over a second dielectric layer overlying the channel region. The transistor is formed by selectively oxidizing portions of a monocrystalline semiconductor substrate and then removing portions of the oxidized substrate. The resulting structure includes a body region of the substrate having overlying first and second oxide regions, with a protruding channel region extending from the body region between the oxide regions.

Abstract: CMOS devices and process for fabricating low voltage, high voltage, or both low voltage and high voltage CMOS devices are disclosed. According to the process, p-channel stops and source/drain regions of PMOS devices are implanted into a substrate in a single step. Further, gates for both NMOS and PMOS devices are doped with n-type dopant and NMOS gates are self-aligned.

Abstract: A first conductive impurity ion is implanted into a semiconductor substrate to form a well area on which a gate electrode is formed. A first non-conductive impurity is implanted into the well area on both sides of the gate electrode to control a substrate defect therein and to form a first precipitate area to a first depth. A second conductive impurity ion is implanted into the well area on both sides of the gate electrode, so that a source/drain area is formed to a second depth being relatively shallower than the first depth. A second non-conductive impurity is implanted into the source/drain area so as to control a substrate defect therein and to form a second precipitate area. As a result, substrate defects such as dislocation, extended defect, and stacking fault are isolated from a P-N junction area, thereby forming a stable P-N junction.

Abstract: A manufacturing process is carried out starting from an SOI type wafer including a top silicon layer and a bottom silicon layer separated from each other by a buried silicon dioxide layer. In the top layer, a LOCOS type sacrificial region is formed and then removed, so as to form a cavity that extends in depth as far as the buried oxide layer. Subsequently, the cavity is filled with epitaxial or polycrystalline silicon, so as to form a power region extending between the top surface and the bottom surface of the wafer; then lateral insulation regions are formed that insulate the power region from the circuitry region.

Abstract: A method of fabricating a defect induced buried oxide (DIBOX) region in a semiconductor substrate utilizing an oxygen ion implantation step to create a stable defect region; a low energy implantation step to create an amorphous layer adjacent to the stable defect region, wherein the low energy implantation steps uses at least one ion other than oxygen; oxidation and, optionally, annealing, is provided. Silicon-on-insulator (SOI) materials comprising a semiconductor substrate having a DIBOX region in patterned or unpatterned forms is also provided herein.

Abstract: The present invention discloses a semiconductor device and its manufacture by which damages, such as cracks, generated by the heat of melting of a fuse that is employed for isolating a circuit from the other circuits, can be blocked from propagating into other parts of the semiconductor device. A lower protective film formed on an oxide film provided on a substrate, has a width larger than that of the fuse, and blocks the propagation of damages generated at melting of the fuse. A first insulating film formed on the oxide film so as to cover the lower protective film, has two grooves reaching the lower protective film that is formed so as to surround the fuse. The fuse is formed in the region between the two grooves formed in the first insulating film. A second insulating film is formed on the first insulating film so as to cover the fuse, and has grooves connected to the grooves formed in the first insulating film.

Abstract: Trench capacitors are fabricated utilizing a method which results in a metallic nitride as a portion of a node electrode in a lower region of the trench. The metallic nitride-containing trench electrode exhibits reduced series resistance compared to conventional trench electrodes of similar dimensions, thereby enabling reduced ground rule memory cell layouts and/or reduced cell access time. The trench capacitors of the invention are especially useful as components of DRAM memory cells having various trench configuration and design.

Abstract: A method of forming a semiconductor device includes forming a moat stack outwardly from a substrate, the moat stack comprising a dielectric pad disposed outwardly from the substrate, a silicon buffer structure disposed outwardly from the dielectric pad, and a protective dielectric cap disposed outwardly from the silicon buffer structure. The method further comprises forming a protective sidewall structure outwardly from at least a sidewall of the silicon buffer structure, forming an isolation dielectric region adjacent to the moat stack, after formation of the isolation dielectric region, removing the protective dielectric cap, and forming a conductive gate comprising the silicon buffer structure.

Abstract: A photoresist pattern is formed on a field oxide film and an element forming region across the field oxide film and the element forming region such that a portion of a surface of the field oxide film and a portion of a surface of a silicon epitaxial layer are continuously exposed. The photoresist pattern is used as a mask to inject boron ions into the silicon epitaxial layer and heat treatment is performed thereon to form an external base containing the relatively significant crystal defect present in the silicon epitaxial layer in the vicinity of the field oxide film. Thus, a semiconductor device can be obtained including a bipolar transistor which provides improved breakdown voltage between the collector and the base and contemplates reduction of current leakage.

Abstract: A fabrication method for a semiconductor memory device having an isolation structure which includes the steps of forming a pad oxide film on a semiconductor substrate, forming a first nitride film on the pad oxide film, patterning the first nitride film and the pad oxide film, forming an oxynitride film on a portion of the substrate externally exposed by the patterning step, forming side walls of a second nitride film on sides of the first nitride film, removing a portion of the oxynitride film using the side walls as a mask, forming a field oxide film on an exposed portion of the substrate, and removing the remaining pad oxide film, first nitride film, second nitride film, and oxynitride film. The first nitrate film and the pad oxide film may be patterned such that the pad oxide film is undercut to expose more of the substrate and to allow formation of the oxynitride film under the first nitride film. As such, the first nitride film can be used as a mask, rendering unnecessary the formation of side walls.

Abstract: A nitride layer is deposited over a field oxide layer used to separate transistors formed in a substrate, the nitride layer serving to decrease transistor current leakage. The nitride layer has a dense lattice, effectively blocking H+ and Na+ penetration from overlying layers into the field oxide. Positive ions such as H+ and Na+ penetrating into the field oxide layer cause a p-substrate under the field oxide layer to become inverted or act like an n-type substrate, creating leakage current between source and drain regions of transistors which the field oxide layer separates. When high transistor threshold voltages such as 12 volts or more are desired, the nitride layer provides a significant reduction in current leakage.

Abstract: The method of the invention starts with forming a mask on a blank wafer, wherein the mask contains a number of openings that expose a portion of the wafer. By performing a wet oxidation process, field oxide is formed on the exposed surface of the wafer. The wafer surface is then become ragged after the mask and the field oxide are removed. In order to further increase the surface area of a dummy wafer, an etching process is performed on the ragged surface after a hemispherical grained layer is formed on the ragged surface.

Abstract: A technique for reducing active area encroachment (birdsbeak) by using a polysilicon hard mask combined with both wet and dry etch for the isolation nitride. This process forms a thinner layer of nitride adjacent the openings for oxide growth, which reduces stress at the silicon/nitride interface. The advantages include control over birdsbeak, reliable gate oxide quality, low junction leakage current, an improved active area, improved isolation, low peripheral junction leakage, and higher field transistor threshold voltage.