Showing papers on "Depletion region published in 1981"

A field-funneling effect on the collection of alpha-particle-generated carriers in silicon devices

Abstract: We studied the transient characteristics of charge collection from alpha-particle tracks in silicon devices. We have run computer calculations using the finite element method, in parallel with experimental work. When an alpha particle penetrates a pn-junction, the generated carriers drastically distort the junction field. After the alpha particle penetration, the field, which was originally limited to the depletion region, extends far down into the bulk silicon along the length of the alpha-particle track and funnels a large number of carriers into the struck junction. After a few nanoseconds, the field recovers to its position in the normal depletion layer, and, if the track is long enough, a residue of carriers is left to be transported by diffusion. The extent of this field funneling is a function of substrate concentration, bias voltage, and the alpha-particle energy.

Power-limiting breakdown effects in GaAs MESFET's

Abstract: State-of-the-art GaAs MESFET'S exhibit an output power saturation as the input power is increased Experiments indicated that this power saturation is due to the combined effects of forward gate conduction and reverse gate-to-drain breakdown This reverse breakdown was studied in detail by performing two-dimensional numerical simulations of planar and recessed-gate FET's These simulations demonstrated that the breakdown occurs at the drain-side edge of the gate The results of the numerical simulations suggested a model of the depletion layer configuration which could be solved analytically This model demonstrated that the breakdown voltage was inversely proportional to the product of the doping level and the active layer thickness

Dynamics of Charge Collection from Alpha-Particle Tracks in Integrated Circuits

Abstract: We studied the transient characteristics of charge collection from alpha-particle tracks in silicon devices. We have run computer calculations using the finite element method, in parallel with experimental work. When an alpha particle penetrates a pn-junction, the generated carriers drastically distort the junction field. After alpha particle penetration, the field, which was originally limited to the depletion region, extends far down into the bulk silicon along the length of the alpha-particle track and funnels a large number of carriers into the struck junction. After less than one nanosecond, the field recovers to its position in the normal depletion layer, and, if the track is long enough, a residue of carriers is left to be transported by diffusion. The extent of this field funneling is a function of substrate concentration, bias voltage, and the alpha-particle energy.

Semiconductor devices controlled by depletion regions

Abstract: A field effect semiconductor device and method of controlling the device by merged depletion regions are provided. The device includes, in combination, first (22) and second (24) spaced apart PN junctions. Depletion regions (36, 38 and 40, 42) associated with the junctions have boundaries displaced from their respective junctions as a function of the doping concentration on either side of the junctions. The junctions are spaced apart by a distance with allows overlap of the depletion regions (38, 40) positioned therebetween. By applying a reverse bias to one (22) of the PN junctions the conductivity on the side (34) of the second PN junction (24) remote from the first PN junction (22) can be varied through the effect of merged depletion regions.

Rapid isothermal annealing of ion implantation damage using a thermal radiation source

Abstract: The rapid annealing of ion implantation damage in silicon using the radiation from a graphite heater has been demonstrated. Complete 3‐in.‐diam wafers were annealed in a single 10‐sec exposure with high activation for implants of boron (50 keV; 1×1015 cm−2) and moderate activation for high‐dose arsenic implants (140 keV; 6×1015 cm−2). Dopant redistribution was ∼1000 A for boron and ∼200 A for arsenic. Leakage currents of implanted p+n and n+p diodes were comparable to those of furnace‐annealed control wafers and indicate good crystallinity in the depletion region near the junction. Diode leakage uniformity across the wafers was also excellent. C‐V measurements on oxides annealed by this technique showed flatband voltages within 0.5 V of those measured on control wafers. This method of annealing implant damage is a practical alternative to those involving more elaborate power sources such as lasers, electron beams, or high‐intensity arc lamps.

Photoelectrochemical Characterization of CdSe Thin Film Anodes

Abstract: Photoelectrochemical characterization of CdSe thin films prepared by achemical solution growth technique was carried out by linear-sweep voltammetry,current-voltage measurements under forward and reverse bias,photocurrent-wavelength measurements, and electrical impedance measurementtechniques. The quality of the present CdSe/electrolyte junctions forphotovoltaic applications was assessed by examining the effect of varyinglight intensity on current-voltage behavior. The ideality factors (n) were determinedfor these junctions by modeling the CdSe/electrolyte junction in termsof a Schottky barrier. Values of n close to 2 were obtained and were attributedto the dominating influence of recombination-generation currents (eitherat the surface or in the depletion region) on the overall photovoltaic characteristics.The presence of a thin, tunnelable CdS layer on the CdSe electrodesurface was postulated as causing the nonideal current-voltage behaviorparticularly in the reverse-bias regime. Equivalent circuits for the CdSe/electrolyte interface were developed using a novel technique for measuringthe equivalent parallel conductance and capacitance as a function ofsignal frequency and applied bias. A method of extracting flatband potentialsbased on conductance measurements is demonstrated using the CdSe thinfilm/electrolyte interface.

Electronic Properties of ZnO Varistors: A New Model

Abstract: Much of the research on ZnO varistors has concentrated on the explanation of their dc current-voltage characteristics. However, varistors also have unusual ac properties which can be technologically important, and must be described by any comprehensive model. In an ideal varistor with identical grain boundaries throughout, there should be no dispersive capacitance at zero bias. In real varistors this capacitance varies considerably with frequency. This dispersion has two causes, charge trapping in the depletion regions and differing grain boundary barriers. Calculations for each process are given. For voltages well below the varistor breakdown value, the low frequency capacitance increases with applied voltage. At even higher voltages the capacitance turns over and becomes negative. All of these effects can be described with a double depletion layer/thermionic emission model. The anomalous capacitance behavior with bias is due to the modulation of the potential barriers by charge trapping at the grain boundaries. In the varistor breakdown regime minority carriers created by impact ionization are important.

Characteristics in InGaAs/InP avalanche photodiodes with separated absorption and multiplication regions

Abstract: Improved characteristics of compound semiconductor avalanche photodiodes with separated absorption and multiplication regions (SAM) are discussed. Temperature dependences of dark current and breakdown voltage show that the tunneling current in the narrow energy gap layer can be suppressed in InGaAs/InP APD's with the SAM structure. Dark currents above punch-through voltages, at which the depletion layer reaches the InP-InGaAs heterointerface, are caused by the generation-recombination process in the InGaAs and at the heterointerface. Dark currents near breakdown depend on the n-layer thickness and are strongly affected by the electric field strength in the ternary layer. Tunneling currents are dominant in diodes with thin n-InP layers, while the generation-recombination processes in the InGaAs layers are dominant in those with a thick n-InP layer. The dark current was as low as 7.8 \times 10^{4} A/cm2at M = 10 when the interface electric field strength is reduced. A maximum multiplication factor of 60 was observed for the 6 \times 10^{-7} A initial photocurrent. Rise time and full width at half maximum in a pulse response waveform were 100 and 136 ps, respectively, at M = 10 .

Depletion layer effects in the open-circuit- voltage-decay lifetime measurement

Abstract: There is a renewal of interest in open circuit voltage decay as a technique for determining the base region minority carrier lifetime in semiconductor diodes. Although the existing theory of open circuit voltage decay provides a substantial foundation for interpreting the experimental data, major features of the decay curves of real silicon diodes cannot be satisfactorily explained unless depletion layer effects are taken into account. Theoretical decay curves are calculated to show the effects of depletion layer capacitance and recombination current on the otherwise ideal open circuit voltage decay. From these and from experimental decay curves, it is shown that each of these depletion layer effects is significant only below a threshold junction voltage that depends upon material parameters of the device.

Photovoltaic and Photoelectrochemical Solar Energy Conversion

Abstract: Recombination in Solar Cells: Theoretical Aspects- 1 Introduction- 2 Conventions Usually Made for p-n Junctions and Solar Cells- 3 Three Laws of Photovoltaics- 4 Maximum Power, Recombination and the Ideality Factor- 5 Junction Currents as Recombination Currents- 6 Steady-State Recombination Rates at a Given Plane X- 7 Junction Model and Space-Dependences- 8 Transition Region Recombination Current Density- 9 The Bulk-Regions Recombination Current Density- 10 Summery of p-n Junction Current Densities from Sections 8 and 9- 11 Configuration and Electrostatics of the Schottky Barrier Solar Cell- 12 The Place of Recombination Effects in (p-type) Schottky Barrier Solar Cells- 13 Recombination Currents and Voltage Drops in (p-type) Schottky Barrier Solar Cells- 14 Conclusion- A Few More General Topics- (I) Thermodynamic Efficiency- (II) Simple Theory to See that an Optimum Energy Gap Exists- (III) Is Dollars per Peak Watt a Good Unit?- (IV) Energy Unit for Global Use- (V) When will Solar Conversion be Economically Viable?- References- Schottky Barrier Solar Cells- 1 Introduction- 2 The Schottky Barrier Cell Principle- 21 Principle of SBSC Operation- 22 Current Transport Mechanism in Schottky Barriers- 23 Effect of the MIS Potential Distribution upon the Diode Quality Factor n- 24 The MIS SBSC under Illumination- 25 The Minority Carrier MIS SB Cell- 3 Solar Cell Parameters and Design Considerations- 31 Metal-Semiconductor Barrier Height- 32 Diode Quality Factor n- 33 Interfacial Oxide Thickness- 34 Transmission Properties of the Metal- 35 Spectral Response- 36 Substrate Resistivity- 37 Substrate Thickness- 38 Series Resistance- 4 Results and Discussion of Typical Silicon MIS Cells- 41 Open Circuit Voltage- 42 Short Circuit Current Density- 43 Fill Factor- 44 Efficiency- 45 The Min MIS Cell- 46 The MIS Inversion Layer Cell- 47 Stability of MIS Solar Cells- 48 The Future for MIS Cells - Cheaper Substrates?- Acknowledgement- References- CdS-Cux S Thin Film Solar Cells- 1 Introduction- 2 CdS Thin Film Technology- 21 Vacuum Vapor Deposition of CdS Films- 22 Sputtering- 23 Spray Deposition- 24 Sintering- 3 CuxS Thin Film Technology- 31 Dipping Process (Wet Process)- 32 Evaporation of CuCl- 33 Evaporation of CuxS- 34 Sputtering of CuxS- 4 Properties of the CdS Layer- 41 Crystallography and Grain Size of CdS Films- 42 Optical Properties of the CdS Films- 43 Luminescence- 44 Electrical Properties of CdS Films- 5 Properties of CuxS Films- 51 Stoichiometry- 52 Coulometric Titration- 53 Optical Properties- 54 Electrical Properties- 6 Properties of the Heterojunction- 61 Structure of the Heterojunction- 62 Surface Effects of the CuxS Film- 63 Capacitance Measurements- 64 Diffusion Length in CuxS and CdS- 65 Spectral Response- 66 Band Diagram- 7 Technology of CdS-CuxS Photovoltaic Generators- 71 Cell Structures- 72 Fabrication Process of CdS-CuxS Cells- 8 Performance Characteristics of Solar Cells and Generators- References- Conversion of Solar Energy Using Tandem Photovoltaic Cells Made from Multi-Element Semiconductors- I Introduction- II Increasing Efficiency by Recourse to Tandem PV Cell Systems- III Design of an Optimized Solar Cell Structure for Tandem Cell Systems- IV Selection of Semiconductors for Tandem Solar Cell Systems- V Optimized Design of Direct Gap Photovoltaic Cells- VI Monolothic and Split Spectrum Tandem Cell Systems- VII Synthesis and Properties of Ternary Alloy Chalcopyrite Semiconductors- VIII Thin Films of CuInSe2 and Solar Cells Made from Them- IX Summary and Conclusions- References- The Principles of Photoelectrochemical Energy Conversion- I Sunlight Conversion into Chemical Energy- Photoredox Reactions- Redox Energies and the Scales of Redox Potentials- Photosynthesis as an Example- Artificial Systems for Energy Conversion- References to Lecture for Further Reading- II Fundamentals of Semiconductor Electrochemistry- The Space Charge Layer- Kinetics of Electron Transfer Reactions- References- III The Semiconductor Electrolyte Contact under Illumination and Photodecomposition Reactions- Distribution of Electrons and Holes under Illumination- Photodecomposition of Semiconductors- References- IV Photoelectrochemical Cells and their Problems- Regenerative Cells- Storage Cells- Energy Conversion Efficiency- References- Photoelectrochemical Devices for Solar Energy Conversion- General Discussion of Photoelectrochemical Devices- Semiconductor Electrolyte Junctions - Conventional Picture- Photo-Induced Charge Transfer Reactions- Semiconductor Electrode Stability- Electrochemical Photovoltaic Cells- Photoelectrosynthetic Cells- Photoelectrolysis Cells- Photocatalytic Cells- General Considerations- Effects and Importance of Surface States- Unpinned Band Edges- Hot Carriers- Surface Modification- Electrochemical Photovoltaic Cells- Reduced Surface and Grain Boundary Recombination- Non-aqueous Electrolytes- Storage Systems- General Status and Prognosis for Electrochemical Photovoltaic Cells- Photoelectrosynthetic Cells- Derivatized Electrodes- Photo-Oxidation and Photo-Reduction on the same Surface and in Particulate System- Dye Sensitization- Layered Compounds and other New Materials- General Status and Prognosis for Photoelectrosynthesis- Acknowledgement- References- The Iron Thionine Photogalvanic Cell- The Reaction Scheme- The Differential Equation- The Characteristic Lengths- The Kinetic Length- Bleaching and the Generation Length- The Recipe for Success- The Electrode Kinetics- Current Voltage Characteristics- Homogeneous Kinetics- The Iron Thionine System- The Reaction Scheme- Quantum Efficiencies- The Parameters- Rotating Transparent Disc Electrodes- The Thionine System- The Synthesis of Modified Thiazine Dyes- The Properties of the Modified Dyes- Self Quenching- Summary of Progress to Date- Electrode Selectivity- The Problem- The Manufacture of the Thionine Coated Electrode- Properties of the Thionine Coated Electrode- Electrode Kinetics- Application to Photogalvanic Systems- The Efficiencies of Photogalvanic Cells- The Concentration of Fe(II)- The Concentration of Ee(III)- The Variation of Power with ?E? and k-2- Variation with pH- Final Summary- Acknowledgements- References- Charge Separation and Redox Catalysis in Solar Energy Conversion Processes- 1 Introduction- 2 Design of Photoredox Reactions for Photodissociation of Water- 21 Photodecomposition of Water in Homogeneous Solutions- 22 Photoproduction of H2 from Water- 221 Photolysis of Simple Ions in Acid Media- 222 Photolysis of Metal Hydrides- 223 H2 Production via Dye-Sensitized Redox Reactions- 224 Photochemistry of Selected Redox Systems for H2 Evolution- 23 Redox Systems for O2-Evolution from Water- 231 Photo-Induced Oxygen Evolution from Water- 3 Stabilization of Redox Intermediates through the Use of Multiphase Systems- 31 Micelles- 311 Photoionisation- 312 Light Induced Electron Transfer in the Micelle- 313 Solution and Spatial Separation of Reactants in Micelles- 314 Functional Micellar Systems- a) Redox Reactions in Transition Metal Ion Micelles- b) Micelles Formed with Crown Ether Surfactants- c) Micelles with Long Chain Derivatives of Sensitizer or Acceptor Relays- 32 Light-Induced Charge Separation in Vesicles- 33 Charge Separation Phenimena in Other Multiphase Systems- 4 Redox Catalysis- 41 Concept of Redox Catalysis- 42 Redox Catalysis in the H2 -Evolution Reaction from Water- 43 Redox Catalysis in the O2Evolution Reaction from Water- 44 Coupled Redox Catalysts for Water Decomposition- 5 Photoelectrochemical Cells Based on Redox Reactions- References- Author Index

Planar doped barrier semiconductor device

Abstract: Disclosed is a majority carrier rectifying barrier semiconductor device housing a planar doped barrier. The device is fabricated in GaAs by an epitaxial growth process which results in an n+ -i-p+ -i-n+ semiconductor structure wherein an extremely narrow p+ planar doped region is positioned in adjoining regions of nominally undoped (intrinsic) semiconductive material. The narrow widths of the undoped regions and the high densities of the ionized impurities within the space charge region results in rectangular and triangular electric fields and potential barriers, respectively. Independent and continuous control of the barrier height and the asymmetry of the current vs. voltage characteristic is provided through variation of the acceptor charge density and the undoped region widths. Additionally, the capacitance of the device is substantially constant with respect to bias voltage.

Method of passivating pn-junction in a semiconductor device

Abstract: The surface termination of a p-n junction of a semiconductor device is passivated with semi-insulating material which is deposited on a thin layer of insulating material formed at the bared semiconductor surface by a chemical conversion treatment at a temperature above room temperature. The layer may be formed by oxidizing the semiconductor material of the body for example in dry oxygen between 300° C. and 500° C. or in an oxidizing liquid containing for example hydrogen peroxide or nitric acid at for example 80° C. The layer is sufficiently thin to permit conduction (e.g. by tunnelling) between the semi-insulating material and the surface but thick enough to reduce said conduction so that when the junction is reverse-biased leakage current flows further along the semi-insulating material before flowing out to the surface across the layer. This increases the spread of the junction depletion layer along the surface thereby permitting a high breakdown voltage even with a high resistivity for the material. The thin layer can also act as a barrier against gettering of lifetime-killers (e.g. gold) from the semiconductor body by the semi-insulating material. The semi-insulating material may be based on amorphous or polycrystalline silicon or a chalcogenide.

Anodic oxide composition and Hg depletion at the oxide–semiconductor interface of Hg1−xCdxTe

Abstract: The composition and chemical states of the oxide, interface, and bulk semiconductor regions of Hg0.8Cd0.2Te with anodic oxide films of 360, 1200, 1600, and 1600 A chemically etched to 1200 A were analyzed with x‐ray photoelectron spectroscopy combined with ion sputterng. The near interface semiconductor exhibits 30%–40% less Hg than the bulk semiconductor. Detailed depth profiles were measured for this Hg depletion region. The maximum depletion is independent of the oxide thickness, but its spatial extent is a function of oxide thickness for thin films. For thick oxide films (≳1000 A) the depletion width is constant at 150–200 A. No significant change in the Cd concentration is seen. Line shape analysis of the Cd M45N45N45 Auger transition in the anodic oxide, CdO, Cd(OH)2, and CdTeO3 suggests that CdTeO3 rather than TeO2, CdO, or Cd(OH)2, is the major constituent of the anodic oxide. The oxide composition is interpreted to be 44% CdTeO3, 29% CdTe2O5, 17% HgTeO3, and 10% HgTe2O5.

Physical mechanisms responsible for short channel effects in MOS devices

Abstract: The physical mechanisms responsible for short-channel effects in MOS devices are described. It is shown that short-channel effects are caused by the penetration of junction fields into the channel region. These fields effectively decrease the substrate doping, thus leading to a lower threshold voltage and a larger depletion region depth. Computer simulations explicitly verify the lower effective substrate doping and larger depletion depth in short-channel devices. The junction fields are found to decay exponentially with distance from the junction edges and to vary sinusoidally in the vertical direction. Both the decay length and the wave length are found to be proportional to (3t ox + W c ). The usefulness of the new physical understanding is demonstrated in a comparison of the short-channel effects of conventional and buried channel MOSFETs using both computer simulation and experimental results. Some of the limitations of charge sharing models are also discussed.

Photoconductive member having barrier and depletion layers

Abstract: A photoconductive member which is stable in its electrical and optical characteristics, not influenced by circumstances for its use, and possesses extremely high sensitivity to light, remarkably high anti-photo-fatigue property, and deterioration-resistant against repeated use, the photoconductive member comprising a substrate; a photoconductive layer; a barrier layer between the substrate and the photoconductive layer, and having a function of substantially inhibiting injection of carriers from the substrate side to the photoconductive layer; and a depletion layer region formed in the interfacial region of the photoconductive layer and the barrier layer, wherein the photoconductive layer and the barrier layer are made of an amorphous material with silicon as a matrix and hydrogen as a constituent atom, a part of the barrier layer is present between the depletion layer region and the substrate in such a thickness that, in order to inhibit injection of the carriers having the same polarity as that of minority carriers in the barrier layer from the substrate side to the photoconductive layer, probability of the carrier reaching the depletion layer region from the substrate side may be substantially neglected, and the photocarriers in the photoconductive layer having the same polarity as that of majority carriers in the barrier layer, among the photo-carriers to be generated in the photoconductive layer by irradiation of electromagnetic waves, are caused to move in the direction of the barrier layer.

Large-area photovoltaic cell

Abstract: In a large-area photovoltaic cell containing a photoactive semiconductor layer which contacts another semiconductor layer, metal or an electrolyte to form a depletion layer, and further containing an electrode and a counter electrode for current collection, the improvement which comprises employing as a substrate for said photoactive semiconducting layer a metallized textile sheet, the metal constituting one of the electrodes, the sheet having been metallized by depositing the metal thereon wet-chemically without current. The metal thickness may be built up with or without current. Such cells have low internal resistances and are highly efficient.

Characteristics of the metal insulator semiconductor structure:AlN/Si

Abstract: Single‐crystal AlN layers have been grown on Si substrates at ∼1200 °C using metalorganic chemical vapor deposition. The metal/AlN/Si MIS structures have been investigated by the MIS conductance method. It was found that the interface‐state density Nss and electron capture cross section σn in the depletion region are of the order of 1011 eV−1 cm−2 and 10−17 cm, respectively.

Method of semiconductor device for generating electron beams

Abstract: The invention relates to a semiconductor cathode and a camera tube and a display tube, respectively, having such a cathode, based on avalanche breakdown in a p-n junction extending parallel to the surface of the semiconductor body. The released electrons obtain extra energy by means of an accelerating electrode provided on the device. The resulting efficiency increase makes the manufacture of such cathodes in planar silicon technology practical. Since the depletion zone of the p-n junction upon avalanche breakdown does not extend to the surface, the released electrons show a sharp, narrow energy distribution. This makes such cathodes particularly suitable for camera tubes. In addition they find application, for example, in display tubes and flat displays.

Tunnel injection controlling type semiconductor device controlled by static induction effect

Abstract: A tunnel injection controlling type semiconductor device comprising a source semiconductor region having a certain conductivity type for supplying carriers, a drain semiconductor region for receiving the carriers, and a gate electrode for controlling the flow of these carriers. A highly-doped semiconductor region having a conductivity type opposite to that of the source semiconductor region is provided in contact with the source region or contained locally in the source region to cause tunnel injection of carriers. The potential level of this highly-doped region is varied by virtue of the static induction effect exerted by the voltage applied to the gate electrode which is provided at a site close to but separate from the highly-doped region, and to the drain semiconductor region.

Theoretical and practical investigation of the thermal generation in gate controlled diodes

Abstract: The different components of thermal generation in a gate controlled diode are studied theoretically and experimentally. Expressions for the generation current in the space charge layer, the diffusion current from the quasi-neutral bulk and the surface generation current are derived for a gated-diode. The width of the generation zone within the space charge layer is calculated as a function of the energy level of the trap and the diode reverse voltage. This leads to a characteristic of the leakage current as a function of the space charge layer width. It is pointed out that the diffusion current can influence the leakage current and cannot be neglected in structures with a low dark current. In the second part the gate controlled diode is used to characterize the thermal generation in structures with a homogeneous and low dark current. A generation lifetime of 5.5 msec and a surface generation velocity at a depleted surface of 1.5 cm/sec is derived. The generation lifetime is found to be constant as a function of depth into the substrate. A considerable diffusion current is measured which is comparable to the generation current in the space charge layer.

Photoeffects in common-source and common-drain microwave GaAs MESFET oscillators

Abstract: Photoeffects in common-source and common-drain mode GaAs MESFET oscillators show that the common-source mode oscillator has an optical-frequency sensitivity approx. 5 times higher than that of the common-drain mode, principally caused by the oscillator frequency dependence upon C gs . Although the photoinduced frequency change can be duplicated by a small decrease (0.2–0.6 V) in gate bias voltage, 1 MHz capacitance data indicates that a change in the effective space charge density in the gate depletion layer (not a change in built-in voltage) is the source of the C gs variation.

On the carrier collection efficiency of amorphous silicon hydride Schottky barrier solar cells: Effects of recombination

Abstract: Exact solutions for the photogenerated carrier densities and the carrier collection efficiency have been found for amorphous silicon hydride (a‐SiHx ) Schottky barrier solar cells. The dependence of the collection efficiency η on the nature of the contacts, and on the four characteristic lengthscales (thickness of a‐SiHx film, hole diffusion length, absorption length, and width of the depletion region) is determined. Strong dependence of η on the width of the depletion region at very short wavelengths and on the hole diffusion length at long wavelengths suggests that the theory presented here can be used for the determination of these parameters from the experimental measurements of η in solar cells with intimate metal/semiconductor contacts.

A Schottky Barrier Type Solar Cell Using Polyacetylene

Abstract: Schottky barrier type solar cells have been fabricated using polyacetylene, (CH)x as the semiconductive material. Under illumination from a tungsten lamp source (40 mW/cm2), Vsc0.4 V, Joc40 µA/cm2 and F.F.0.25 were obtained. The energy conversion efficiency is estimated to be 0.2% relative to the energy absorbed within the depletion region.

Method for making a semiconductor capacitor

Abstract: This disclosure is directed to an improved semiconductor capacitor structure especially useful in an integrated semiconductor structure with an MOS device and fabrication methods therefor. This semiconductor capacitor is particularly useful for forming the capacitor portion of a single MOS memory cell structure in a dynamic MOS random access memory which utilizes one MOS device in combination with a capacitor. In one specific disclosure embodiment, the semiconductor capacitor comprises a boron (P) implanted region in a substrate of P- type conductivity followed by a shallow arsenic (N) implant into the boron implanted region. The boron implanted region provides a P type conductivity which has a higher concentration of P type impurities than the concentration of impurities contained in the substrate which is of P- type conductivity. Thus, the boron implanted region performs the important function of preventing a surface N type inversion layer from being formed across the semiconductor surface beneath the silicon dioxide insulating layer which could occur across the substrate P- surface if the arsenic implant region was made into the P- substrate without the P type boron implant. The arsenic implant is of N type conductivity and has a higher concentration of impurities than the boron implant region. The dielectric portion of the semiconductor capacitor is the portion of the silicon dioxide layer located on the surface of the arsenic implanted region. A doped polysilicon electrode is formed over this portion of the silicon dioxide insulating layer and provides the other plate of the capacitor structure. In another embodiment that is disclosed, this above described semiconductor capacitor structure or device is combined with an MOS device in a single integrated semiconductor structure in order to provide a single MOS memory cell for dynamic random access memory chip utilizing the MOS device and the capacitor. Preferably, the semiconductor capacitor is shown as a connected extension of either the source or drain region of the MOS device.

Semiconductor device with selective nitride layer over channel stop

Abstract: A semiconductor device comprises a semiconductor body of one conductivity type, at least one semiconductor region of the opposite conductivity type formed in the semiconductor body and having a surface flush with the surface of the semiconductor body, an insulative or semi-insulative film formed on the semiconductor body or semiconductor region through a passivation layer and having a fixed charge, positive or negative, and an electrode metal layer connected to at least one of the semiconductor body and region and formed locally on the film directly or through a passivation layer. The semiconductor body or region is of N conductivity type when the film has a positive fixed charge and of P conductivity type when the film has a negative fixed charge.

Model for Localized States Distribution and Light Dependent Effects in Amorphous Silicon Solar Cells

Abstract: The localized state density for amorphous Si (aSi) can be reasonably approximated by a U-shaped hyperbolic function for the theoretical analysis of the potential profile in the depletion layer of aSi Schottky barrier solar cells. The photocurrent dependence on the width of the depletion layer has been theoretically analyzed with emphasis on the effect of minority carrier recombination in the depletion layer and the shrinkage of the depletion width under sunlight due to hole trapping. The detailed analysis shows that the minority carrier diffusion length Lp is about 0.15 µm and the optimum width of the undoped layer in Schottky barrier solar cells is in the range of 0.2–0.44 µm for the minimum density of gap states of 1017–1016 cm-3eV-1, respectively.

Alternative mechanism for substrate minority carrier injection in MOS devices operating in low level avalanche

Abstract: The mechanism proposed by Matsunaga et al to explain the injection of minority carriers into the substrate of a saturated n-channel MOST cannot account for the size of the observed current An alternative mechanism is suggested based on optical generation of minorities by radiation emitted by hot carriers in the drain depletion region Evidence for this mechanism is presented