Showing papers on "Schottky diode published in 1973"

Effect of alloying behavior on the electrical characteristics of n‐GaAs Schottky diodes metallized with W, Au, and Pt

Abstract: Electrical studies of W/n‐GaAs Schottky diodes have shown that aging at 350 or 500 °C does not significantly change the forward I‐V characteristics of the diodes. Using 4He+ backscattering analysis, it is shown that the W/GaAs interface of simulated diodes does not exhibit any evidence of interdiffusion or reaction. By contrast, considerable alloying occurs in both Au/GaAs and Pt/GaAs systems. In the former, Ga outdiffuses to the surface of Au and Au diffuses into GaAs upon aging at 250 or 350 °C; this has the effect of decreasing the barrier height φB from 0.9 to [inverted lazy s] 0.6 V and increasing the ideality parameter n from 1.0 to [inverted lazy s] 1.2. Interdiffusion in the Pt/GaAs couples, aged at 500 °C, results in the formation of a layered arrangement of type PtGa/PtAs2/GaAs. The PtAs2/n‐GaAs interface is associated with a slightly higher φB ([inverted lazy s] 0.89 V) than that found for the Pt/n‐GaAs interface (φB [inverted lazy s] 0.84 V).

The C-V characteristics of Schottky barriers on laboratory grown semiconducting diamonds

Abstract: Measurements of the differential capacitance of evaporated gold Schottky barriers on laboratory-grown, boron-doped semiconducting diamonds have been obtained for the first time as functions of reverse-bias voltage, frequency, and temperature The data are analyzed on the basis of a model which includes the effects of long time constants for hole capture from the deep (boron) level, as well as previously unobserved effects due to the series resistance of the bulk The barrier height at 300°K is found to be 1·73 ± 1·10 eV , in good agreement with the ‘one-third band gap’ value of Mead and Spitzer Excellent correlation is found between optical transmission measurements and the C-V analysis for the uncompensated boron concentration, indicating that all of the optically observable dopant is electrically active By fitting the model with two adjustable parameters at room temperature, good agreement is obtained between measured and calculated capacitance over two and a half decades as a function of temperature The analysis indicates that the activation energy of the acceptor level is 0·26–0·37 eV for the samples studied, while the associated capture cross-sections are 0·9–2·0 × 10 −17 cm 2

Minority carrier effects upon the small signal and steady-state properties of Schottky diodes

Abstract: Schottky diode theory is re-evaluated by applying the combined thermionic emission-diffusion theory to both the majority and minority carrier flows across the metal-semiconductor contact. Under both steady-state d.c. and small signal a.c. conditions, numerical solutions to the semiconductor transport equations subject to boundary conditions determined from the combined theory are used to investigate the effects of minority carriers upon the properties of uniformly doped Schottky diodes. High injection effects and contact limitations are shown to influence the minority carrier injection ratio and the total stored minority carrier charge. It is further shown that the small signal impedance of a large class of Schottky diodes becomes inductive under moderate forward bias.

Silicon Schottky retinas for infrared imaging

Abstract: Silicon Schottky barrier diode arrays, operating in a high sensitivity storage mode, provide the basis for a new class of IR imaging sensor. A Pd on p-Si retina which has a wavelength dependent quantum efficiency from 1 to 3.5 µm is described, This device has a noise equivalent temperature of .17K against a 300K background. The operating temperature is 120K and retina nonuniformities cause negligible reduction in sensitivity.

The effect of an interfacial layer on minority carrier injection in forward-biased silicon Schottky diodes

Abstract: It is shown that the degree of minority carrier injection in Au-Si junctions can be substantially increased by the inclusion of a thin interfacial layer between the metal and the semiconductor. When a forward voltage is applied to the junction, a part of this voltage is developed across the interfacial layer. This favours the reduction of the barrier height to minority carriers, which tunnel from the metal into the semiconductor. The minority carrier injection current increases at the expense of the majority carrier current. For a given oxide thickness, γ(= Jminority/Jtot) increases with forward bias, approaching a saturation value for a few volts applied to the junction. For a given voltage, γ also shows a variation with interfacial layer thickness, δ, and the present results indicate that an oxide thickness can be chosen to optimise γ. In the case of a gold-silicon junction with an insulating layer of thermally-grown oxide, as δ is increased to 40 A, the saturation value of γ increased from 10 −4 for δ = 10 A through a maximum of 2 × 10−1 for δ ⋍ 30 A. For oxides prepared by r.f. sputtering, the maximum value of γ is 10−1 and occurs for δ ⋍ 80 A. These results are of considerable importance in the improvement of injection luminescence in metal-semiconductor diodes.

Rectification, space‐charge‐limited current, photovoltaic and photoconductive properties of Al/tetracene/Au sandwich cell

Abstract: Tetracene thin films sandwiched between two evaporated metal electrodes show rectification and photovoltaic effects. The rectification does not follow the J‐V equation for Schottky barriers or p‐n junctions. A theory is presented to explain the rectification and photovoltaic response. The forward current of the diode (Au positive) is space‐charge‐limited current (SCLC) and is attributed to hole injection from the gold electrode. The forward current varies as Vl+1/d2l+1, where V is the voltage, d the thickness and 1=(Tc/T)∼3. The SCLC is related to an exponential distribution of traps ∼7×1019/cm3. Other results related with trapping are also presented. No variation of capacitance with voltage is found, indicating that the tetracene film is completely depleted. In the photovoltaic mode, the Au electrode is positive and the Al negative. The photovoltaic current and voltage are related by the relation V=V0(1−e−aJ). The short‐circuit photocurrent varies as Fn where n varies between 0.6 and 1 and F is the incid...

Periods of p-adic Schottky groups.

Abstract: An element g £ G is called hyperbolic, if it is represented by a matrix whose characteristic roots have different absolute values. A subgroup Γ < G is called Schottky group, if it is finitely generated and every g € Γ, g Φ e is hyperbolic. A Schottky group is free (Ihara) and discrete. Let Σ be the closure of the set of fixed points of elements of Γ in P g. In fact, Σ Jr. So this note can be looked at s a very natural morphism from Mumford [3] to Mumford [4]. Our restriction by p-adic case is most probably inessential but significantly simplifies the exposition.

Frequency dependence of C and ΔV/Δ(C−2) of Schottky barriers containing deep impurities

Abstract: The frequency dependence of ΔV/Δ(C −2 ) of Schottky barriers with deep impurities has been discussed on the basis of the depletion approximation. Systematic treatment has been developed of Schottky barriers having spatially distributed deep centers and useful expressions have been derived for ΔV/Δ(C −2 ) . It is shown that the impurity profile, the energy level and the electron emission rate of deep impurities can be determined by making measurements of the frequency dependence of ΔV/Δ(C −2 ) . The method of measuring ΔV/Δ(C −2 ) has also been briefly described.

Unified theory of high‐frequency noise in Schottky barriers

Abstract: A unified noise‐temperature equation is presented which describes the high‐frequency noise (>1/f noise) characteristic of Schottky barrier diodes from above room temperature to cryogenic temperatures. The unified noise equation takes into consideration the dominant transport mechanism of the barrier and is applicable to any metal‐semiconductor system. Noise‐temperature measurements on fabricated Schottky barrier diodes at 18, 77, and 300 °K confirm the validity of the noise theory presented.

Metal-germanium Schottky barriers

Abstract: A systematic study has been made of the electrical characteristics of Schottky barriers fabricated by evaporating various metal films on n -type chemically cleaned germanium substrates. The diodes, with the exception of AlGe contacts, exhibit near-ideal electrical characteristics and age only slightly towards lower barrier height values. AlGe contacts exhibit very pronounced ageing towards higher barrier height values, due to formation of an extra aluminium oxide interfacial layer. Because of this, the barrier height values of aged AlGe contacts derived from I - V and C - V characteristics differ significantly. The dependence of the barrier height, ( φ b ) on the metal work function, φ m , for different metal-germanium contacts shows that surface states play an important role in the formation of the barrier. The density of germanium surface states is estimated to be D s = 2 × 10 13 eV −1 cm −2 .

Photoconductive gain greater than unity in CdSe films with Schottky barriers at the contacts

Abstract: Photoconductive gains greater than unity can be obtained by illuminating a homogeneous photoconductor having blocking contacts with band gap radiation. A model is presented, which conceives such a possibility. Au contacts to CdSe form a Schottky barrier at the interface. Upon illumination the photogenerated holes are trapped in the Schottky barrier, shrinking the barrier and allowing injection of electrons in the CdSe. This gives rise to the possibility of gain greater than unity. Experimental evidence supporting the model is presented. Photoconductive gains as large as 300 have been measured when these films were illuminated with a photon flux of 2×1015 photons/cm2/sec.

Point‐cathode electron sources‐electron optics of the initial diode region

Abstract: A realistic model of a point‐cathode electron source is analyzed in this paper, and its electron optical properties are discussed. Both cathode and anode are modeled as equipotential surfaces of a sphere on orthogonal cone (SOC). The model predicts that the radius of the apparent electron source produced by this diode may be as small as 2–3 nm for field emitters and as small as 4–6 nm for strong‐field Schottky emitters. This source is found to be a virtual image of the emitting area of the cathode. The image position and magnification are determined for different representative cathode shapes, and quantitative results are also presented on geometric aberrations, effects arising from the initial energies of emission, and on source current and current density. An optimum cathode apex radius for smallest source sizes is predicted to be about 200 nm for field emission and about 700 nm for Schottky emission. These results are compared with those from the often used, but less accurate, sphere model.

Electrical and mechanical features of the platinum silicide‐aluminum reaction

Abstract: The electrical and mechanical features of a thermally induced interaction between platinum silicide and aluminum have been investigated. It has been found that a diffusion‐controlled reaction occurs between these two materials which results in conversion of platinum silicide to the intermetallic PtAl2. The activation energy for this process is found to be 0.77 eV. As platinum silicide Schottky diodes with aluminum contacts are sintered for increasing time periods, this reaction propagates to the platinum silicide‐silicon interface and the effective barrier height of the metal‐semiconductor junction is observed to drop sharply to a value below that of aluminum‐silicon Schottky diodes. As longer sinter cycles are performed the effective barrier height rises to a value characteristic of aluminum‐silicon contacts. This effect is shown to be a result of diffusion of aluminum through the reacted material and the formation of an essentially aluminum‐silicon contact at the silicon substrate. The mechanical features of the platinum silicide‐aluminum reaction observed on test devices are correlated with the electrical effects of this reaction noted on Schottky diodes.

The superconductor‐semiconductor Schottky barrier diode detector

Abstract: The superconductor‐semiconductor contact diode, or super‐Schottky‐barrier‐diode, has been examined theoretically and experimentally as a video detector of high‐frequency radiation. The measured noise‐equivalent power (NEP) of the device is believed to be the smallest value ever reported in the literature for video detection. Moreover, the high reliability established for the ordinary Schottky barrier diode is in evidence for the proposed diode. The doping of the semiconductor is chosen large enough so that electron tunneling dominates the volt‐ampere behavior of the diode. As such, for T < Tc and V < Δ, the diode exhibits a high degree of nonlinearity in its volt‐ampere characteristic. It is this nonlinearity that the super‐Schottky‐diode exploits. Initial results with p‐type GaAs at 1 °K have yielded an NEP of 2 × 10−15 W/Hz1/2 at 10 GHz.

Electroluminescence in forward-biased zinc selenide Schottky diodes

Abstract: Schottky diodes consisting of a metal contact on n -type ZnSe emit light when biased in the forward direction if there is a layer of insulating or semi-insulating material between the metal and the semiconductor. The electroluminescence spectrum is characteristic of luminescent centres in the ZnSe. There is a threshold voltage for electroluminescence which corresponds to the difference between the metal Fermi level and the top of the valence band of the semiconductor. For gold on ZnSe the threshold voltage is 1·3 V. Characteristics of the device differ from those of similar MIS systems because the oxide used here has appreciable conductivity.

Bias-dependent phase delay of Schottky contact microstrip line

Abstract: Schottky contact lines are a form of microstrip on a semiconducting substrate, the strip of which forms a rectifying metal–semiconductor contact. Such a line has an extremely low phase velocity that is determined by the ratio of the depletion-region width to the substrate thickness, i.e. by the bias. Measurements agree well with theoretical expressions that are deduced from a parallel-plate-waveguide model.

Schottky barrier diode semiconductor structure and method

Abstract: Schottky barrier diode semiconductor structure having a semiconductor body formed essentially of silicon and having a surface with an active device formed in the semiconductor body having collector, base and emitter regions and with at least two metals on said surface combining with the silicon to form an alloy of at least two metals and silicon which is in contact with the collector, base and emitter regions and also extends beyond the base region to form a Schottky barrier diode having a barrier height which is determined by the composition of the alloy. In the method, the alloy of at least the two metals in combination with the silicon is adjusted to modify the barrier height of the Schottky barrier diode so that a barrier height can be chosen ranging from between 0.64 and 0.835.

Nonlinear Analysis of the Schottky-Barrier Mixer Diode

Abstract: The waveshape of the local-oscillator voltage component that exists across the nonlinear junction of a Shottky-barrier diode is a fundamental determinant of mixer performance. This waveshape significantly differs from that of the total local-oscillator voltage impressed across the diode terminals since it is influenced by parasitic, particularly spreading resistance and contact inductance, which exist in series with the junction. The junction-voltage waveshapes resulting from a 9.375-GHz sinusoidal local-oscillator generator voltage are computed for three common equivalent-circuit models of the diode. In the first model the diode is represented by a nonlinear conductance in series with a fixed spreading resistance. The second model includes the nonlinear capacitance associated with the junction, and the third additionally includes the contact inductance. In each case, the junction-voltage waveshape is significantly nonsinusoidal. It is shown that the contact inductance can induce a peak inverse junction voltage that greatly exceeds the peak voltage impressed across the diode terminals. This parasitic reactance thus can have an important bearing on the burnout properties of the mixer diode.

Laser diode package formed of ceramic and metal materials having high electrical and thermal conductivity

Abstract: A laser diode package which has little inherent induction at high frequency, due to its size and geometry, and allows operation of the diode at reduced temperature without affecting the temperature of the optically coupled medium.

Au - (n-type) InP Schottky barriers and their use in determining majority carrier concentrations in n-type InP

Abstract: The electrical characteristics of Au - (n-type) InP Schottky barriers fabricated on etched surfaces are reported. The barrier height of the junction is low (040 eV), and from this value of barrier height the surface state model of {110} etched InP is shown to be in line with the general picture for other III-V compounds. Measurements are also reported of n-type InP carrier concentration determination in the range 5×1015-4×1016 cm−3 using conventional Schottky barrier C-V analysis. For voltages greater than a few tenths of a volt reverse bias this procedure yields values of carrier concentration that are in good agreement with values determined by Hall measurements. Below this voltage the capacitance data are no longer representative of carrier concentration in the normal way due to the onset of incomplete depletion of mobile carriers in the barrier region.

Epitaxial V-groove bipolar integrated circuit process

Abstract: A new four-mask "V-groove" process for the fabrication of bipolar integrated circuits has been developed. The process utilizes epitaxial ν/n+/n-layers and anisotropic etching of \langle100\rangle silicon to eliminate the buried layer and isolation diffusions as well as the need for masking the base diffusion of the standard six-mask bipolar integrated circuit process, n-p-n transistor, resistor, and Schottky diode characteristics are equivalent to or exceed those of the standard process. A five-mask V-groove process provides improved lateral p-n-p transistors compared with the four-mask approach. The V-groove integrated circuit structure offers simpler processing, smaller isolation capacitances, lower parasitic collector resistances, larger packing densities, and higher junction breakdown voltages than standard bipolar integrated circuits without degradation of other properties.

Schottky Energy Calculations for the Alkali Halides; Details and Results of Successive Approximations

Abstract: Results of theoretical determinations of the energy to form a Schottky defect, using a point-dipole model, are presented for alkali halides of the NaCl structure. The calculations were made under the following conditions: (1) Region I (in which the electrostatic and short-range interactions for each ion are treated in detail) contained 6, 18, 26, and 32 ions respectively. (2) Short-range parameters were determined from both the elastic and dielectric properties and the results compared. The "dielectric" parameters produced a better match between the dielectric properties of regions I and II (the dielectric continuum region) and showed better agreement with experimental values for the Schottky energy. (3) Derivations of detailed expressions and calculations were performed independently in two laboratories and cross-checked to eliminate errors.Region I displacements which are presented for the four cases indicate that an instability occurs in the 32-ion case for crystals in which the ions differ considerabl...

Monolithically integrable digital basic circuit

Abstract: Disclosed is a circuit showing a switching transistor whose base is connected to diodes forming the logical inputs and whose collector forms the logical output. Power supply is effected by charge carrier injection into the emitter of the switching transistor. To this end, a complementary transistor is employed, whose emitter terminal is connected to a voltage source and whose collector and base are linked with the base and the emitter of the switching transistor respectively. The collector of the switching transistor and the diodes are made up of Schottky contacts on the semiconductor zone forming the base of the switching transistor. Also disclosed is a semiconductor structure of the circuit consisting of a layered structure with a first, second, and third semiconductor layers of alternating conductivity types. The first and second layers are ohmically contacted, whereas the third layer is provided with the Schottky contacts. The second layer simultaneously forms the emitter of the switching transistor and the base of the complementary transistor whose emitter is made up of the first layer. The third layer simultaneously forms the collector of the complementary transistor and the base of the switching transistor.

Deep trap levels of ion‐implanted germanium in silicon measured by Schottky contact techniques

Abstract: Differential capacitance measurements on Schottky contacts can be used to determine energy level, charge, and concentration profile of ion‐implanted impurities which cause deep trap levels in the semiconducting material. For the example of germanium implanted into silicon, two deep donor levels at Ec − E 1 = 0.27 eV and E 2 − Ev = 0.51 eV are found which are due to an unstable incorporation of the implanted germanium in the silicon lattice. For the stable incorporation which is obtained at high annealing temperatures, no isoelectronic levels are found for germanium on lattice sites in silicon.

Light emission from hot electrons in zinc sulphide

Abstract: Measurements are made of the luminescence from hot electrons in ZnS Schottky diodes. The luminescence, which consists of a broad band in the visible and near infrared, is interpreted in terms of transitions of hot electrons within the conduction band. Information on the conduction band structure is obtained from the shape of the spectrum. Information about the hot-electron distribution is obtained from measurements of the intensity of the emission as a function of field.

Advantages of Mott barrier mixer diodes

Abstract: It is shown that the high-frequency performance of miter diodes can be appreciably improved by employing a Mort barrier instead of a Schottky barrier. The larger junction diameters possible with Mott structures also allow a better burnout capability and improved mechanical stability.

Photoluminescence ofn-GaAs at transparent Schottky contacts

Abstract: Near-bandgap photoluminescence at 300 K of a Se-dopedn-GaAs crystal withn=4.8·1016 cm−3 was measured at a transparent CrAu−GaAs Schottky contact. The dependence of the luminescence intensity on the applied reverse voltage was recorded. Both the doping concentration and absorption coefficients above bandgap are determined.