Abstract: A method for extracting a shielding element from a processing chamber of a substrate processing system or inserting the shielding element into the processing chamber is provided. The substrate processing system includes the processing chamber, a first shielding element for excluding application of material onto parts of a substrate, and a substrate transportation system for transporting substrates or substrate carriers into and out of the processing chamber. The method includes transporting the first shielding element by the substrate transportation system.

Abstract: In a plasma enhanced physical vapor deposition of a material onto workpiece, a metal target faces the workpiece across a target-to-workpiece gap less than a diameter of the workpiece. A carrier gas is introduced into the chamber and gas pressure in the chamber is maintained above a threshold pressure at which mean free path is less than 5% of the gap. RF plasma source power from a VHF generator is applied to the target to generate a capacitively coupled plasma at the target, the VHF generator having a frequency exceeding 30 MHz. The plasma is extended across the gap to the workpiece by providing through the workpiece a first VHF ground return path at the frequency of the VHF generator.

Abstract: A method for manufacturing an acoustic wave device with an excellent frequency-temperature profile is performed such that the acoustic wave device produced includes a piezoelectric substrate, an IDT electrode located on the piezoelectric substrate, and a dielectric film mainly including Si and O and arranged on the piezoelectric substrate to cover the IDT electrode. The dielectric film is formed by sputtering in a sputtering gas containing H2O.

Abstract: Provided are a rotating-element spectroscopic ellipsometer and a method for measurement precision prediction of a rotating-element spectroscopic ellipsometer, a recording medium storing program for executing the same, and a computer program stored in a medium for executing the same, and more particularly, a rotating-element spectroscopic ellipsometer and a method for measurement precision prediction of a rotating-element spectroscopic ellipsometer capable of calculating the measurement precision of the rotating-element spectroscopic ellipsometer based on a theoretical equation on standard deviations of ellipsometric parameters for a sample, a recording medium storing program for executing the same, and a computer program stored in a medium for executing the same.

Abstract: The invention relates to apparatus and a method for depositing material onto substrates, particularly optical substrates, to form a coating thereon. The apparatus and method incorporates the use of a series of magnetrons provided to be controlled to sputter deposit material provided in targets mounted therein, on to the substrates. There is provided a voltage to the magnetrons to operate the same and the level of voltage which is required to form required coating or coating layer characteristics is determined by using monitoring apparatus, at least when forming the coating or coating layer for the first time. The appropriate voltage level data for operation of the magnetrons can be held in a database and subsequently used to control the voltage level when forming an identified coating or layers of coatings.

Abstract: Techniques include receiving a design of an integrated computational element (ICE), the ICE design including specification of a substrate and a plurality of layers, their respective target thicknesses and complex refractive indices, complex refractive indices of adjacent layers being different from each other, and a notional ICE fabricated in accordance with the ICE design being related to a characteristic of a sample; forming at least some of the plurality of layers of the ICE in accordance with the ICE design; performing at least two different types of in-situ measurements; predicting, using results of the at least two different types of in situ measurements, performance of the ICE relative to the ICE design; and adjusting the forming of the layers remaining to be formed, at least in part, by updating the ICE design based on the predicted performance.

Abstract: Systems, methods and apparatus for regulating ion energies in a plasma chamber and chucking a substrate to a substrate support are disclosed. An exemplary method includes placing a substrate in a plasma chamber, forming a plasma in the plasma chamber, controllably switching power to the substrate so as to apply a periodic voltage function (or a modified periodic voltage function) to the substrate, and modulating, over multiple cycles of the periodic voltage function, the periodic voltage function responsive to a defined distribution of energies of ions at the surface of the substrate so as to effectuate the defined distribution of ion energies on a time-averaged basis.

Abstract: The present invention generally relates to a vertical CVD system having a processing chamber that is capable of processing multiple substrates. The multiple substrates are disposed on opposite sides of the processing source within the processing chamber, yet the processing environments are not isolated from each other. The processing source is a horizontally centered vertical plasma generator that permits multiple substrates to be processed simultaneously on either side of the plasma generator, yet independent of each other. The system is arranged as a twin system whereby two identical processing lines, each with their own processing chamber, are arranged adjacent to each other. Multiple robots are used to load and unload the substrates from the processing system. Each robot can access both processing lines within the system.

Abstract: In-line metallizer assemblies can include an external rotating actuator exchange that can be operable to exchange one or more parts between a conveyor system and a vacuum chamber, and an internal rotating actuator exchange within the vacuum chamber that can be operable to receive the one or more parts from the external rotating actuator exchange, transition the one or more parts to a sputter coater integrated with the vacuum chamber for metallizing, and return metallized one or more parts to the external rotating actuator exchange such that the external rotating actuator exchange can return the metallized one or more parts to the conveyor system.

Abstract: In forming alumina films on substrates by sputtering of an aluminum metal target in an oxidizing gas-containing atmosphere, film formation is carried out intermittently in a plurality of substeps while restricting a thickness of the film formed in each substep to at most 5 nm. A turntable is disposed to face a direction of sputtering of the aluminum metal target and the substrates are fixed to the turntable.

Abstract: The present invention provides a film forming apparatus and a film forming method which are unlikely to be affected by changes in size and shape of a shield board caused by a recovery process. A film forming apparatus includes a shield board surrounding a sputtering space between a process-target substrate on a stage and a target facing each other in a vacuum chamber, and forms a film on the process-target substrate by causing at least one kind of reactive gas and a film forming material to react with each other. The film forming apparatus is configured to control a ratio of the flow rate of the gas to be introduced into the sputtering space to the flow rate of the gas to be introduced into a space between an inner wall of the vacuum chamber and the shield board, based on a pressure value of the sputtering space measured by pressure detection means.

Abstract: The present invention provides an indium target and manufacturing method thereof, where deposition rate is high, initial discharge voltage is low, and deposition rate and discharge voltage, from the start of sputtering to the end of sputtering, are stable. In the indium target, an aspect ratio (length of longer direction/length of shorter direction) of crystal particle, observed from cross-section direction of the target, is 2.0 or less.

Abstract: To control reactive magnetron sputtering process using a reactive gas or reactive gases the process overall pressure is regulated by means of the flow of the reactive gas or the reactive gases, respectively. Oscillations of the flow of the reactive gas or the reactive gases, respectively are determined and used as feedback to determine the process overall pressure.

Abstract: The present invention concerns a sputtering magnetron assembly comprising a rotatable tubular target cathode and a magnetic field generating device installed within the tubular target cathode. At least part of the magnetic field generating device is configured to move within the tubular target cathode so as to maintain within a predetermined range a magnetic field strength at an outer surface of the tubular target cathode during erosion of said outer surface. The present invention also relates to a physical vapour deposition method using such a sputtering magnetron assembly.

Abstract: There is provided an AC power supply for a sputtering apparatus in which the AC power supply can prevent the induction of an arc discharge by suppressing an overvoltage to be generated when the polarity of each electrode is reversed. A bridge circuit made up of a plurality of switching transistors SW1-SW4 is disposed between positive and negative DC current output lines from a DC electric power supply source. An inductor DCL which makes a DC output to have a constant-current characteristic is disposed in at least one of the positive and the negative DC output lines from the DC electric power supply source to the bridge circuit, and a snubber circuit is disposed in parallel with inputs of the bridge circuit.

Abstract: A method of depositing a layer of a material on a substrate is described. The method includes igniting a plasma of a sputter target for material deposition while the substrate is not exposed to the plasma, maintaining the plasma at least until exposure of the substrate to the plasma for deposition of the material on the substrate, exposing the substrate to the plasma by moving at least one of the plasma and the substrate, and depositing the material on the substrate, wherein the substrate is positioned for a static deposition process.

Abstract: The invention relates to a method for determining the reactive gas consumption in a coating process using plasma, comprising the following steps: a) admitting reactive gas into a coating chamber, wherein the corresponding reactive gas flow is measured and, at the same time, the partial pressure prevailing in the coating chamber is measured, without igniting a plasma; b) admitting reactive gas into a coating chamber, wherein the corresponding reactive gas flow is measured and, at the same time, the partial pressure prevailing in the coating chamber is measured, wherein a plasma is ignited.

Abstract: In a method for forming a metal fluoride film, a metal fluoride film is formed on a substrate by sputtering using a metal target and a mixed gas containing O2 gas and a reactive gas being a fluorocarbon gas.

Abstract: The system and method of the instant invention utilizes a color sensor in order to monitor and control the application of a coating to a substrate when such coating is transferred onto a substrate from a deposition source. Application of the coating to the substrate is terminated when the color sensor detects a pre-programmed end point evidencing the application of an appropriate coating determined by its color.

Abstract: In a method for coating a substrate in a vacuum chamber having a rotating magnetron, wherein a substrate is guided past the magnetron in a substrate transport direction and is coated by a material, which has been isolated from a target connected to the magnetron, and, optionally with the material reacting with a reactive gas present in the vacuum chamber, homogeneity of the coating layer on a substrate is improved by stabilizing the working point by way of the target rotation. This is achieved in that a periodic change of a first process parameter caused by the target revolution is compensated for by a periodic change of a second process parameter having a determined level and/or by employing two magnetrons having different rotational speeds.

Abstract: Embodiments of the invention provide sputtering targets utilized in physical vapor deposition (PVD) and methods to form such sputtering targets. In one embodiment, a sputtering target contains a target layer disposed on a backing plate, and a protective coating layer—usually containing a nickel material—covering and protecting a region of the backing plate that would otherwise be exposed to plasma during the PVD processes. In many examples, the target layer contains a nickel-platinum alloy, the backing plate contains a copper alloy (e.g., copper-zinc), and the protective coating layer contains metallic nickel. The protective coating layer eliminates the formation of highly conductive, copper contaminants typically derived by plasma erosion of the copper alloy contained within the exposed surfaces of the backing plate. Therefore, the substrates and the interior surfaces of the PVD chamber remain free of such copper contaminants during the PVD processes.

Abstract: An inline deposition control apparatus for a vacuum deposition apparatus having one or more deposition sources for depositing one or more deposition layers on a substrate, includes one or more light sources adapted to illuminate the substrate having the one or more deposition layers; a detection arrangement adapted for spectrally resolved detection of a measurement signal, wherein the measurement signal is selected from at least one of: light reflected at the substrate having the one or more deposition layers, and light transmitted through the substrate having the one or more deposition layers; an evaluation unit to determine the respective thicknesses of the one or more layers based on the measurement signal; and a controller connected to the evaluation unit and connectable to the deposition apparatus for feed-back control of the deposition of the one or more deposition layers based on the determined thicknesses. Furthermore, a method of inline deposition control is provided.

Abstract: There is provided a system and method for sputtering a tensile silicon nitride film. More specifically, in one embodiment, there is provided a method comprising introducing nitrogen gas into a process chamber, wherein the process chamber includes a target comprising silicon, placing the process chamber into a transition region between a metallic region and a poisoned region, and applying a voltage to the target.

Abstract: A sputtering apparatus includes a substrate holder which holds a substrate to be rotatable in the plane direction of the processing surface of the substrate, a substrate-side magnet which is arranged around the substrate and forms a magnetic field on the processing surface of the substrate, a cathode which is arranged diagonally above the substrate and receives discharge power, a position detection unit which detects the rotational position of the substrate, and a controller which controls the discharge power in accordance with the rotational position detected by the position detection unit.

Abstract: An assembly sheet includes a plurality of suspension boards and a frame member that integrally supports the suspension boards. On a surface of the frame member, a plurality of identification marks for identifying respective positions of the suspension boards in automatic optical inspection are provided corresponding to the suspension boards.

Abstract: A deposition method for electrochromic WOx films involves cyclic deposition of very thin poisoned and metallic tungsten oxide layers to build up a film with a desired general stoichiometry with x in the range of 3>x>2.75. The method may include: charging a deposition chamber with oxygen gas to poison a tungsten metal target; initiating sputtering of the target while reducing the oxygen partial pressure being supplied to the chamber and pumping the chamber; sputtering target for time t1+t2 to form first and second tungsten oxide layers, where the first layer is deposited during time t1 from a poisoned target and the second layer is deposited during time t2 from a metallic target, and where the stoichiometry of the film comprising the first and second layers is a function of t1 and t2; and, repeating until a desired film thickness is achieved.

Abstract: A system and method for managing power delivered to a processing chamber is described. In one embodiment current is drawn away from the plasma processing chamber while initiating an application of power to the plasma processing chamber during an initial period of time, the amount of current being drawn away decreasing during the initial period of time so as to increase the amount of power applied to the plasma processing chamber during the initial period of time.

Abstract: A method of depositing lithium-containing films on a battery substrate in a sputtering chamber is provided. At least one pair of sputtering targets that each comprise a lithium-containing sputtering member is provided in the sputtering chamber, the sputtering targets selected to each have a conductivity of at least about 5×10?6 S·cm?1. A substrate carrier holding at least one battery substrate is placed in the sputtering chamber. A pressure of sputtering gas is maintained in the sputtering chamber. The sputtering gas is energized by applying to the pair of sputtering targets, an electrical power at a frequency of from about 10 to about 100 kHz.

Abstract: A gas manifold for delivery gas to a sputtering chamber is provided with ports to accommodate plasma emission monitors to monitor plasma information in the sputtering chamber to provide feedback control. The collimators of the plasma emission monitors is exposed to gas flow and thus coating of the monitor is greatly reduced.

Abstract: The invention relates to methods and devices for producing one or more low-particle layers on substrates in a vacuum. The layers are deposited onto the substrate from a cylindrical source material, optionally together with a reactive gas component, by means of magnetron sputtering. The layer is deposited against the force of gravity in a sputter-up method. During the method or within the device, the structure or stochiometric atomic composition of the layers can optionally be modified using a plasma source. Multiple sputtering sources with different source materials can be provided in the device such that multiple layers of different compositions can be applied on the substrate at a high speed in one process.

Abstract: An apparatus and method for controlling an application of power to power a plasma chamber. A detector detects actual power out from the power stage to the plasma chamber during a sampling interval. A compare module compares the actual power out during the sampling interval to a present power setting during the sampling interval and generates a compensation value. An adjust module updates the present power setting for the power stage with the compensation value to provide a new power setting for the power stage to control the power out from power stage to the plasma chamber during the deposition process whereby power losses occurring during the deposition process are compensated during the deposition process. If there is a fixed time period for the deposition process, the compensation method and apparatus may be used to compensate the deposition process for energy losses without extending the duration of the deposition process.

Abstract: Embodiments of the invention provide a manufacturing method which permits a high quality perpendicular magnetic recording medium to be manufactured with a high yield by preventing abnormal discharge which sputters particles from the target. In one embodiment, while the perpendicular magnetic recording medium is formed, DC pulses are applied to the target. During the reversal period (Reversal Time) between sputtering periods, a voltage of the opposite polarity is applied. During the sputtering period, a negative voltage is applied which biases the target surface to a negative potential, causing Ar+ to collide with and sputter CoCrPt and SiO2 for deposition on the intermediate layer. The top surface of the insulation material (SiO2) on the target is charged by Ar+ to have a voltage larger than the target voltage. However, arcing can be prevented since the charge on the surface of the insulation material is neutralized due to a positive voltage applied to the target during the non-sputtering period.

Abstract: When a film is formed by using a sputter method, distribution variation due to a progress of target erosion generated during the film formation is suppressed, and film thickness distribution and resistance value distribution are corrected to an optimal state. In order to maintain the magnetic flux density formed on the target surface at a constant level, the distance between the target surface and the magnet surface (MT distance) is corrected in accordance with the progress of the target erosion. Further, two or more MT distances are set by a process recipe or the like while forming a thin film, and different distribution shapes are combined to form a near flat distribution shape.

Abstract: Methods and systems for in situ measuring sputtering target erosion are disclosed. The emission of material from the sputtering target is stopped, a distance sensor is scanned across a radial line on the sputtering target. The sputtering chamber contains a controlled environment separate and distinct from the environment outside the chamber, and the controlled environment is maintained during the scanning The resulting distance data is converted into a surface profile of the sputtering target. The accuracy of the surface profile can be less than about ±1 ?m. The distance sensor is protected from deposition of the material from the sputtering target. End-of-life for a sputtering target can be determined by obtaining a surface profile of the sputtering target at regular intervals and replacing the sputtering target when the thinnest location on the target as measured by the surface profile is below a predetermined threshold.

Abstract: When a magnetron is scanned about the back of a target in a selected complex path having radial components, the erosion profile has a form depending upon the selection of paths. A radial erosion rate profile for a given magnetron is measured. Periodically during scanning, an erosion profile is calculated from the measured erosion rate profile, the time the magnetron spends at different radii, and the target power. The calculated erosion profile may be used to indicate when erosion has become excessive at any location prompting target replacement or to adjust the height of the magnetron above the target for repeated scans. In another aspect of the invention, the magnetron height is dynamically adjusted during a scan to compensate for erosion. The compensation may be based on the calculated erosion profile or on feedback control of the present value of the target voltage for a constant-power target supply.

Abstract: A deposition method comprises flowing a first gas into a metallization zone maintained at a first pressure. A second gas flows into a reaction zone maintained at a second pressure. The second pressure is less than the first pressure. A rotating drum includes at least one substrate mounted to a surface of the drum. The surface alternately passes through the metallization zone and passes through the reaction zone. A target is sputtered in the metallization zone to create a film on the at least one substrate. The film on the at least one substrate is reacted in the reaction zone.

Abstract: The present invention provides a reactive sputtering method and a reactive sputtering apparatus which suppress a film quality change caused by a temperature variation in continuous substrate processing. An embodiment of the present invention performs reactive sputtering while adjusting a flow rate of reactive gas according to the temperature of a constituent member facing a sputtering space. Specifically, a temperature sensor is provided on a shield and the flow rate is adjusted according to the temperature. Thereby, even when a degassing amount of a film adhering to the shield changes, a partial pressure of reactive gas can be set to a predetermined value. For a resistance change layer constituting a ReRAM, a perovskite material such as PrCaMnO3 (PCMO), LaSrMnO3 (LSMO), and GdBaCoxOy (GBCO), a two-element type transition metal oxide material which has a composition shifted from a stoichiometric one, such as nickel oxide (NiO), vanadium oxide (V2O5), and the like are used.

Abstract: The invention relates to a method and to a device for reversing the feeding of a sputter coating system, particularly when coating a photovoltaic module, in clean rooms, having the following characteristics: a) a transport frame (11) for receiving a substrate wafer (19) of a photovoltaic module, b) a rotary device having means for mounting the transport frame (11), having means for rotating the transport frame (11), and having means for transporting the transport frame (11), c) means for precisely aligning the rotary device relative to the sputter coating system, d) a detection device (18) for checking a sputter process, and computer program having a program code for performing the process steps.

Abstract: A method of forming a film, including the steps of preparing a base plate having a first region and a second region comprised of mutually different materials wherein at least one of the materials is an oxide and selectively conducting a film deposition on either one of the first region and the second region by a bias sputtering. Both the first and second regions can be formed of an oxide. Further, provided is a vapor film deposition method including irradiating a substrate having a plurality of regions of different constituent element groups composed of at least one element with a source material element group composed of at least one element to be deposited and ionized elements.

Abstract: A method including directing a first radiation at a first copper-indium-gallium (CIG) sputtering target in a reactive copper indium gallium selenide (CIGS) sputtering process, detecting a first reflected radiation from the first CIG target and determining the amount of selenium poisoning of the first CIG target based on the first reflected radiation.

Abstract: A control system and method for controlling two motors determining the azimuthal and circumferential position of a magnetron rotating about the central axis of the sputter chamber in back of its target sputtering and capable of a nearly arbitrary scan path, e.g., with a planetary gear mechanism. A system controller periodically sends commands to the motion controller which closely controls the motors. Each command includes a command ticket, which may be one of several values. The motion controller accepts only commands having a command ticket of a different value from the immediately preceding command. One command selects a scan profile stored in the motion controller, which calculates motor signals from the selected profile. Another command instructs a dynamic homing command which interrogates sensors of the position of two rotating arms to determine if the arms in the expected positions. If not, the arms are rehomed.

Abstract: Methods and apparatuses for performing combinatorial processing are disclosed. Methods include introducing a substrate into a processing chamber. The processing chamber includes a sputter assembly disposed over the substrate. The sputter assembly includes a rotatable n-fold, symmetric-shaped magnetron and a sputter target. The methods include depositing a first film on the surface of a first site-isolated region of the substrate. The methods further include depositing a second film on the surface of a second site-isolated region of the substrate. Furthermore, methods include evaluating results of the first and second films.

Abstract: A film formation apparatus and film formation method that improve film thickness uniformity. A rotation mechanism holds a target having a sputtered surface in a state inclined relative to a surface of a substrate. The rotation mechanism rotatably supports the target about an axis extending along a normal of the sputtered surface. The target supported by the rotation mechanism is sputtered to form a thin film on the surface of the substrate. When forming the thin film, the rotation mechanism maintains the rotational angle of the target.

Abstract: A sputtering magnetron for coating a substrate includes a target and a magnet system that can be displaced relative to one another. The magnet system forms a magnetic field that penetrates the target, and has a support apparatus, a support plate with magnets arranged thereon, and actuators. The support apparatus is connectable to the support plate by the actuators such that distance between the magnet system and the target can be set, at least in sections. A cooling circuit cools the magnet arrangement and the target by a coolant. A layer measuring device obtains data of layer properties of at least one layer deposited on the substrate. Magnet system controls evaluate the data obtained and generate manipulated variables employed as the input variables of the actuators. A method for dynamically influencing the magnetic field is also provided.

Abstract: In a simple method and device for producing plasma flows of a metal and/or a gas electric discharges are periodically produced between the anode and a metal magnetron sputtering cathode in crossed electric and magnetic fields in a chamber having a low pressure of a gas. The discharges are produced so that each discharge comprises a first period with a low electrical current passing between the anode and cathode for producing a metal vapor by magnetron sputtering, and a second period with a high electrical current passing between the anode and cathode for producing an ionization of gas and the produced metal vapor. Instead of the first period a constant current discharge can be used. Intensive gas or metal plasma flows can be produced without forming contracted arc discharges. The selfsputtering phenomenon can be used.

Abstract: A magnetron sputtering apparatus of the invention includes: a sputtering chamber in which a target can be opposed to an object to be subjected to film formation; a gas introduction port facing the sputtering chamber; a magnet provided outside the sputtering chamber and opposite to the target and being rotatable about a rotation center which is eccentric with respect to center of the magnet; a sensor configured to detect a circumferential position of the magnet in a plane of rotation of the magnet; and a controller configured to start voltage application to the target to cause electrical discharge in the sputtering chamber on the basis of the circumferential position of the rotating magnet and gas pressure distribution in the sputtering chamber.

Abstract: A method and control system are provided for depositing a layer in a sputter-deposition system having a target cathode. A first dependence relationship of a deposition rate of the layer on an operating parameter, selected from cathode voltage, cathode current, and cathode power, is provided prior to deposition of the layer. A second dependence relationship of the operating parameter on time is measured during deposition of the layer, while a different operating parameter, also selected from cathode voltage, cathode current, and cathode power, is held substantially constant. On the basis of the first and second dependence relationships, a deposition time for the layer is dynamically determined during deposition of the layer.

Abstract: A sputtering method includes receiving etch time information for a first substrate detected in a dry etching process, calculating a deposition time for a second substrate from the etch time information for the first substrate, and executing sputtering for the second substrate based the calculated deposition time. The thickness of the thin film deposited on the substrate in the sputter device may be uniformly maintained by using etch end point information detected in an end point detection (EPD) device. A sputtering system comprises a sputter device for executing a sputtering process for depositing a thin film on a substrate by a sputtering method, an EPD device for generating EPD information including etch time information for the substrate for a calculation of a deposition time during which the thin film is deposited, and a controller for calculating a deposition time by using the EPD information, and for controlling the sputter device based on the calculated deposition time.

Abstract: The present invention provides a method of controlling a reactive sputtering system used in coating processes. More specifically, the present invention provides a microprocessor-based control system for reactive gases in a sputtering system, particularly during the start-up phase of operation. The preferred demand for such a reactive gas is predicted for every stage of the operation, and the reactive gas supply is amenable to predictive control provided by object program-driven mathematical formulae. The injection of reactive gas using time-advanced, sequential, mathematically-derived procedures simplifies overall system operation and provides a system with an optimal amount of reactive gas at an optimal time.

Abstract: A transparent conductive laminate having a completely crystallized, transparent conductive layer on a substrate comprising an organic polymer molding, and a process for producing the same. The transparent conductive layer is excellent in transparency and wet heat confidence and is not excessively low in specific resistivity. The transparent conductive laminate includes a substrate comprising an organic polymer molding having formed thereon a completely crystallized, transparent conductive layer comprising an In.Sn composite oxide having an amount of Sn atom of 1 to 6% by weight based on the total weight of In atom and Sn atom and having a film thickness of 15 to 50 nm, a Hall mobility of 30 to 45 cm2/V·S, and a carrier density of from 2×1020/cm3 to 6×1020/cm3.