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Showing papers on "Field effect published in 1982"


Book
18 Mar 1982
TL;DR: In this article, the authors present a method for extracting interface trap properties from the conductance of a metal oxide Silicon Capacitor at intermediate and high frequency intervals, and demonstrate that these properties can be used for charge trapping in the oxide.
Abstract: Introduction. Field Effect. Metal Oxide Silicon Capacitor at Low Frequencies. Metal Oxide Silicon Capacitor at Intermediate and High Frequencies. Extraction of Interface Trap Properties from the Conductance. Interfacial Nonuniformities. Experimental Evidence for Interface Trap Properties. Extraction of Interface Trap Properties from the Capacitance. Measurement of Silicon Properties. Charges, Barrier Heights, and Flatband Voltage. Charge Trapping in the Oxide. Instrumentation for Measuring Capacitor Characteristics. Oxidation of Silicon--Oxidation Kinetics. Oxidation of Silicon--Technology. Control of Oxide Charges. Models of the Interface. Appendices. Subject Index. Symbol Index.

2,101 citations


01 Jan 1982
TL;DR: In this article, the authors present a method for extracting interface trap properties from the conductance of a metal oxide Silicon Capacitor at intermediate and high frequency intervals, and demonstrate that these properties can be used for charge trapping in the oxide.
Abstract: Introduction. Field Effect. Metal Oxide Silicon Capacitor at Low Frequencies. Metal Oxide Silicon Capacitor at Intermediate and High Frequencies. Extraction of Interface Trap Properties from the Conductance. Interfacial Nonuniformities. Experimental Evidence for Interface Trap Properties. Extraction of Interface Trap Properties from the Capacitance. Measurement of Silicon Properties. Charges, Barrier Heights, and Flatband Voltage. Charge Trapping in the Oxide. Instrumentation for Measuring Capacitor Characteristics. Oxidation of Silicon--Oxidation Kinetics. Oxidation of Silicon--Technology. Control of Oxide Charges. Models of the Interface. Appendices. Subject Index. Symbol Index.

1,855 citations


Journal ArticleDOI
TL;DR: The photofield effect has been shown to be a promising new tool for studying both electron and hole photoconductivity in the same sample as mentioned in this paper, and the first direct evidence has been obtained for an increase in N F(E) as a-Si: H is annealed above T A ∼ 300°C or after prolonged exposure to light.
Abstract: The field effect has been examined as a technique for determining the density of gap states in a-Si: H. It gives the field-effect density of states N F(E) to an accuracy of a factor of two and is therefore most useful for studying changes in a sample as it undergoes a series of treatments. Using the field effect the first direct evidence has been obtained for an increase in N F(E) as a-Si: H is annealed above T A ∼ 300°C or after prolonged exposure to light. The photofield effect is shown to be a promising new tool for studying both electron and hole photoconductivity in the same sample.

45 citations


Journal ArticleDOI
TL;DR: In this paper, the authors measured the field effect conductance of α-Si:H and its dependence on annealing to 180°C and illumination with white light, and found that illumination produces changes in the Fermi level with respect to the conduction band mobility edge.
Abstract: We have measured the field effect conductance of α‐Si:H and its dependence on annealing to 180 °C and illumination with white light. We find that illumination produces changes in the field effect conductance which are completely reversed by annealing. Illumination produces a decrease in the off conductance between a factor of 5 and 30 times, together with a shift of the threshold voltage. We interpret the effect of illumination as a modification of the density or occupancy of deep states in such a way that the bulk Fermi level is moved with respect to the conduction band mobility edge. Space‐charge regions can exist at either or both interfaces of the α‐Si:H film and these are very sensitive to interface conditions. The magnitude of the surface band bending is modified by electron trapping in the gate insulator (SiN), which is brought about by bias‐ temperature stressing. Annealing to 180 °C causes the detrapping of excess electrons in the SiN layer, reversing the effect of positive bias‐temperature stres...

44 citations


Journal ArticleDOI
TL;DR: In this article, an exact theory for the electronic density of bulk gap states in amorphous semiconductors from field effect and capacitance-voltage measurements is presented, where the analytical expression for the density of the gap states is given as a function of the surface potential of amorphou semiconductor.
Abstract: An exact theory for the calculation of the electronic density of bulk gap states in amorphous semiconductors from field effect and capacitance-voltage measurements is presented. The analytical expression for the density of the gap states is given as a function of the surface potential of amorphous semiconductors. It is also shown that the influence of surface states on the measured gap states can be completely eliminated by combining a capacitance-voltage method with a field effect technique.

44 citations


Journal ArticleDOI
TL;DR: In this paper, an accurate model for junction field effect transistors (JFETs) and Schottky barrier field-effect transistors with micron and submicron dimensions is presented.
Abstract: An accurate model for junction field-effect transistors (JFETs) and for Schottky barrier field-effect transistors (MESFETs) with micron and submicron dimensions is presented. The following effects are modeled: distributed channel charge, electrostatic drain feedback, drift velocity saturation, channel length modulation, substrate bias effect, subthreshold region effect, short-length and narrow-width effects, drain-source punch-through, variable capacitance effects, and temperature effects. It is primarily physical rather than empirical and only one set of parameters is needed to simulate devices of a particular technology. The model is intended for silicon devices, but the extension to devices in semiconducting III – V compounds and with insulating substrates is straightforward. The model is compared to experimental data.

32 citations


Journal ArticleDOI
TL;DR: In this article, high field conduction in n+nn+ amorphous hydrogenated silicon (α•Si:H) films has been investigated at different temperatures, and the results can be explained by assuming space charge limited conduction (SCLC) with a uniform density of traps.
Abstract: High field conduction in n+nn+ amorphous hydrogenated silicon (α‐Si:H) films has been investigated at different temperatures. The results can be explained by assuming space‐charge limited conduction (SCLC) with a uniform density of traps. The value of density of states at the Fermi level, g(EF), obtained from the SCLC measurements ranges between 7−9×1016 cm−3 eV−1. Similar values are obtained by measurements of field effect and frequency and temperature dependence of Schottky barrier capacitance on material grown under identical conditions.

29 citations


Journal ArticleDOI
TL;DR: In this article, the effects of visible light and applied electric field on the properties of the HgCdTe-anodic oxide interface were investigated and the photoinduced surface charging was attributed to internal photoemission.
Abstract: This paper reports the effects of visible light and applied electric field on the properties of the HgCdTe–anodic oxide interface. The surfaces of anodized n‐type crystals are accumulated with a fixed positive charge in the oxide on the order of 5×1011 cm−2. However, illumination with photons of energy ?2.2 eV can neutralize and even invert these surfaces. The original surface charge is restored by placing the sample in the dark for periods of minutes at room temperature and weeks at 77 K. Based on our measurement of the oxide energy gap of 3.4 eV, the photo‐induced surface charging is attributed to internal photoemission of electrons from the HgCdTe valence band to the oxide conduction band. These photoemitted electrons fall into deep traps in the oxide and neutralize the fixed positive charge. When stored in the dark, these trapped electrons are thermally excited from the traps and recombined in the semiconductor. Charge exchange between the oxide traps and semiconductor can also be promoted by applying...

19 citations


Patent
03 Jun 1982
TL;DR: In this paper, a chemically sensitive field effect device has its chemically selective system exposed to the material being investigated, and a protected reference electrode is also in contact with the body under investigation, and is biased at a predetermined DC level relative to the chemically sensitive device.
Abstract: A chemically sensitive field effect device has its chemically selective system exposed to the material being investigated. The device is driven by a time varying, typically sinusoidal, current source. A protected reference electrode is also in contact with the body under investigation, and is biased at a predetermined DC level relative to the chemically sensitive field effect device.

18 citations


Journal ArticleDOI
TL;DR: In this paper, first-order time-dependent perturbation theory is used to derive expression for scattering rates in the presence of high electric fields, and it is suggested that the complicated retarded transport equations recently introduced into hot electron theory are not necessary to treat the intra-collisional field effect in the weak phonon coupling limit.
Abstract: First-order time-dependent perturbation theory is used to derive expression for scattering rates in the presence of high electric fields. Analysis in terms of Houston functions suggests that scattering rates are approximately field independent, but a more accurate treatment in terms of Airy functions shows that at sufficiently high fields, the resonant width of the scattering vertex is limited by the domain of integration, and a field dependent suppression of scattering occurs. This effect occurs first for small-wavevector phonons, and appreciable effects are expected for fields exceeding 104-105 V cm-1. It is also suggested that the complicated retarded transport equations recently introduced into hot electron theory are not necessary to treat the intra-collisional field effect in the weak phonon coupling limit at fields of interest in conventional semiconductor transport. At fields where suppression of scattering is significant, it is found that additional scattering into field-induced band tails is also important.

18 citations


Patent
29 Mar 1982
TL;DR: In this paper, a Schottky field effect transistor with contact elements having different barrier heights is defined, i.e., a circuit containing at least one Schottkysmoid transistor with different barrier height.
Abstract: Electronic circuit containing at least one Schottky field effect transistor with contact elements having different Schottky barrier heights.

Proceedings ArticleDOI
01 Jan 1982
TL;DR: In this paper, the influence of grain boundaries on the electrical characteristics of polysilicon transistors is investigated, where the grain size is assumed to be of the same order of magnitude as the channel dimensions, and a 2D study of the band curvature near a grain boundary is carried out in order to estimate the evolution of the grain-boundary-induced potential barrier versus late voltage.
Abstract: The influence of grain boundaries on the electrical characteristics of polysilicon transistors is investigated. The grain size [a few microns) is assumed to be of the same order of magnitude as the channel dimensions, which is the case in laser recrystallized polysilicon films. A 2-D study of the band curvature near a grain boundary in a MOSFET was carried out in order to estimate the evolution of the grain-boundary-induced potential barrier versus Late voltage. Expressions of the drain current have been derived and are compared with device-measured characteristics. The viability of integrated circuits made in large grain polysilicon films is also discussed.

Journal ArticleDOI
TL;DR: The discrepancy in the measured gap-state density between the present method and the DLTS or ICTS techniques does not arise from the presence of surface states, but from differences in the electronic properties of a-Si:H.


Journal ArticleDOI
TL;DR: In this paper, the static characteristics of hydrogenated amorphous silicon thin-film transistors are theoretically studied based on the analysis of field effect in a-Si:H MOS structures.
Abstract: The static characteristics of hydrogenated amorphous silicon thin-film transistors are theoretically studied based on the analysis of field effect in a-Si:H MOS structures. The TFT characteristics are obtained for typical cases of the gap state density distributions and the results showed that the slope of the state density distribution near and above the Fermi-level is a key factor to determine the on/off current ratio of a-Si:H TFTs.

Journal ArticleDOI
TL;DR: In this paper, the field effect-derived DOS is shown to depend strongly on the properties of the film/substrate interface: equivalent bulk DOS estimates range from 5 × 10 16 to greater than 10 19 eV −1 cm −3 at the Fermi level.

Journal ArticleDOI
TL;DR: In this article, the field effect conductance of hydrogenated amorphous silicon thin-film transistors has been calculated as a function of the gate voltage, taking into account the space charge due to excess free carriers, in addition to that caused by modulation of bulk localized state occupancy, and the charge in the surface states in the determination of the boundary condition.
Abstract: The field‐effect conductance of hydrogenated amorphous silicon thin‐film transistors has been calculated as a function of the gate voltage. This analysis differs from the existing ones in taking into account (1) the space charge due to excess free carriers, in addition to that caused by modulation of bulk localized state occupancy, and (2) the charge in the surface states in the determination of the boundary condition. Numerical results are presented to demonstrate the significance of these effects.

Journal ArticleDOI
TL;DR: In this paper, temperature dependence of dark conductivity and field in a chemically vapor-deposited amorphous SiNx (x 0.2) alloy is presented, and the gap-state density near the Fermi level in the CVD a-SiNx film is evaluated as 2×1018 cm-3 eV-1 which is one-fifth of that in an undoped film.
Abstract: Temperature dependence of dark conductivity and field in a chemically vapor-deposited amorphous SiNx (x0.2) alloy are presented. The a-SiNx film exhibits little hopping conduction and large field effect as compared with undoped CVD a-Si. The gap-state density near the Fermi level in the CVD a-SiNx film is evaluated as 2×1018 cm-3 eV-1 which is one-fifth of that in an undoped film.


Journal ArticleDOI
TL;DR: In this paper, a simple method, based on the variation of the size of the field generating electrodes, to correct the measured field effect is described, which can be used to determine the dependence of the elastic stiffness of an applied dc field by means of ultrasonic velocity measurements.
Abstract: The determination of the dependence of the elastic stiffnesses of an applied dc field (electroelastic effect) by means of ultrasonic velocity measurements presents difficulties when electric fields perpendicular to the propagation direction are applied. In such a geometry the field is disturbed by the transducer. The magnitude of the field therefore varies along the path of the ultrasonic pulses. A simple method, based on the variation of the size of the field generating electrodes, to correct the measured field effect is described.

Journal ArticleDOI
TL;DR: In this paper, the authors present experimental results on measurements of density of states at the Fermi level of samples prepared in their laboratory from silane-hydrogen mixture, and show that estimates of density as obtained from field effect in coplanar structures, temperature and frequency dependence of capacitance of Schottky diodes and space charge limited conduction in n+nn+ structures are in general agreement with one another.



Journal ArticleDOI
TL;DR: In this article, a noncherenkovian mechanism was proposed for the optic phonons flux amplification in semiconductors under a strong constant electric field associated with the field effect on the acts of electron-phonon interactions.

Journal ArticleDOI
TL;DR: In this paper, field effect studies have been made on the electrical properties of a silver mica p-type SnTe thin film metal insulator-semiconductor structure in the temperature range 100 to 300 K. The results have been explained on the basis of a two valence band model of SnTe.
Abstract: Field effect studies have been made on the electrical properties of a silver mica p‐type Sn Te thin film metal‐insulator‐semiconductor structure in the temperature range 100‐300 K. It has been observed that the Hall coefficient decreases with an increase in the negative gate field, while the effect of a positive gate field is the opposite. The mobility, however, increases with an increase in the positive gate field in the low temperature region, and decreases sharply as the temperature increases. The negative field, on the other hand, reduces the mobility in the whole temperature range. The results have been explained on the basis of a two valence band model of Sn Te.



Journal ArticleDOI
TL;DR: In this paper, a very thin p+/n+ structure was used to replace the conventional Schottky barriers for the first time, which is known as the "camel diode gate FET".
Abstract: Normally-on GaAs field effect transistors (FETs) having 1 µm gate lengths and 4 µm channel lengths were fabricated in structures grown by molecular beam epitaxy (MBE). The unique part of this device is the very thin p+/n+ structure used to replace the conventional Schottky barriers. The device fabrication procedure is identical to that of a Schottky barrier FET (MESFET), but the devices exhibit characteristics similar to that of a junction field effect transistor (JFET). This new device, the "camel diode gate FET", is expected to have applications in both logic and power devices.

Patent
10 Jul 1982
TL;DR: In this paper, a P-N junction diode for prevention of destruction provided in an MOS field effect type semiconductor circuit device to be used both as a field film destruction prevention element by a method wherein the PN junction was provided in parallel with a resistor circuit connected in series to a gate, and the diode thereof was arranged at the lower part of the field insulating film in a pad region.
Abstract: PURPOSE:To make a P-N junction diode for prevention of destruction provided in an MOS field effect type semiconductor circuit device to be used both as a field film destruction prevention element by a method wherein the P-N junction diode for prevention of destruction is provided in parallel with a resistor circuit for prevention of destruction connected in series to a gate, and the diode thereof is arranged at the lower part of the field insulating film in a pad region. CONSTITUTION:A P type diffusion layer 7 is provided at the lower part of a field insulating film 2 at the lower part of an input/output terminal 1 to constitute a P-N junction diode for prevention of destruction, and a terminal 5 is provided to constitute also a resistor for prevention of destruction. Accordingly when an abnormal voltage is applied to the input/output terminal, the forward directional or the reverse directional current path of the diode is formed to perform protective action, and a voltage generated during the delay time of operation of the diode is not applied directly to a gate film owing to action of the resistor. Therefore because electric potential difference between the input/output terminal and the substrate at the lower part of the field film is eliminated, destruction of the field film is not generated, and effective utilization of the substrate at the lower part of the pad can be attained to enhance integration.

Book ChapterDOI
01 Jan 1982
TL;DR: The Schottky barrier structures have been made with n-type hydrogenated amorphous silicon (a-Si:H) prepared by the glow discharge decomposition of SiH4 and the density of gap states N(E) in the depletion layer of these diodes has been determined by analyzing the current transients caused by the emission of electrons after removal of a small forward bias.
Abstract: Schottky barrier structures have been made with n-type hydrogenated amorphous silicon (a-Si:H) prepared by the glow discharge decomposition of SiH4 The density of gap states N(E) in the depletion layer of these diodes has been determined by analysing the current transients caused by the emission of electrons after removal of a small forward bias Depending on the preparation conditions, the dopant concentration and the history of the structures (exposure to light, electron bombardment) N(E) near midgap ranges from 31015 to 10l8cm-3 The distribution of states is more similar to that deduced from field effect and space charge limited current data than to DLTS results