Showing papers on "Diode published in 1973"

Electron and hole ionization rates in epitaxial silicon at high electric fields

Abstract: Ionization rates for electrons and holes are extracted from photomultiplication measurements on silicon p+n mesa diodes for electric fields of 2·0 × 105−7·7 × 105 V/cm at temperatures of 22, 50, 100 and 150°C. These results are particularly pertinent to the analysis of high-frequency (∼ 100 GHz) silicon IMPATT diodes. The rates obtained here are in reasonable agreement with previously published data of van Overstraeten and DeMan, although slightly larger in magnitude. Calculated curves of breakdown voltage vs background doping level are presented using the room temperature ionization rates. Also a comparison is made to previously reported rates. The new rates provide a closer agreement between predicted and measured breakdown voltages for breakdown voltages less than 70 V.

cw degradation at 300°K of GaAs double-heterostructure junction lasers. II. Electronic gain

Abstract: The rapid degradation at 300°K in the cw regenerative output of stripe‐geometry GaAs double‐heterostructure junction lasers is shown to be a result of the formation of a local optical absorber in the laser cavity. Gain measurements performed on diodes before and after degradation show that the optical loss within the cavity increases during degradation. By observing the (predominantly) spontaneous emission from the active region directly through the n‐GaAs substrate, it is confirmed that the increased loss is localized in a region where little or no spontaneous emission takes place at lasing energies. In such diodes, the internal radiative efficiency of the undegraded portion of the optical cavity shows a relatively small decrease compared to the external differential quantum efficiency. When the local absorber extends over a sufficient length of the cavity the electronic gain in the undegraded section is insufficient to overcome the loss and the device ceases to act as a regenerative optical oscillator. Net gain measurements on DH laser devices in which the active region is lightly (≈ 1017) n‐doped indicate that the optical gain increases linearly with current prior to degradation. At lasing threshold the medium exhibits net gain over a wavelength range of 100 A. After degradation the gain dependence on current can become superlinear due to the saturation of the optical absorber. Estimates on the attenuation constant in the local absorber at low currents give a value of ≈ 60 cm−1 at 8800 A. For pulsed currents close to lasing threshold the attenuation constant increases to nearly 160 cm−1 at 8760 A.

Schottky barrier height of n‐InxGa1−xAs diodes

Abstract: The barrier heights φB of Au/n‐InxGa1−xAs diodes are measured by the capacitance‐voltage and saturation current methods. The composition dependence of the barrier height is φB (eV) = 0.95 − 1.90x + 0.90x2. A low barrier height with a relatively wide band gap is obtained in this system.

Detection of optical and infrared radiation with DC-biased electron-tunneling metal-barrier-metal diodes

Abstract: The voltage obtained from metal-barrier-metal (MBM) diodes by phase-sensitive detection when illuminated with optical and near-infrared radiation, modulated at 880 Hz, has been studied as a function of an applied dc bias. The detected voltage is a nonlinear function of the bias voltage for high junction impedances, and linear for low junction impedances. The nonlinearity in the junction has been shown to be consistent with electron tunneling theory.

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.

Zinc oxide light emitting diode

Abstract: A light emitting diode comprising a single crystal of high efficiency violet fluorescing zinc oxide together with an ohmic cathode and a rectifying anode secured thereto. The diode emits near band-gap radiation at room temperature when energized with low D.C. voltage. The produced light is believed to be associated with radiative recombination of free excitons.

Second breakdown and damage in junction devices

Abstract: Second breakdown has been studied in silicon-on-sapphire (SOS) thin-film diodes using the stroboscopic technique of Sunshine. Nucleation of current filaments, filament growth, and damage through the formation of melt channels are observed and related to the voltage waveforms, geometry, and base layer resistivity. The delay time and the minimum energy for the onset of second breakdown are related to heating of the high-resistivity side of the junction. Theoretical models are presented to describe nucleation of current channels in the junction and the melt transition. A junction channel forms when the sum of minority carrier and thermally generated current densities becomes equal to the local applied current density. The voltage across the junction then goes close to zero locally, but the internal field is not "washed out." The channel is ballasted by the spreading resistance of the high-resistance region. The melt transition is described in terms of a single heat-transfer coefficient characteristic of the device type. As the melt filament grows, the voltage across the filament (and the device) falls. The threshold current for filamentation varies as (ρ-3/4), where ρ is the resistivity of the high-resistance region. Data on transistors are presented in support of the theoretical models.

Nonlinear properties of IMPATT devices

Abstract: The basic principles of IMPATT diodes as microwave devices are reviewed and the current status of these devices concerning power output and efficiency is given. The main purpose of this paper, however, is to discuss the nonlinear properties of these diodes which are useful in the design of amplifiers, oscillators, and other microwave devices. The main results of this paper are obtained from a digital computer analysis where an approximate, but realistic, diode model is employed. A detailed comparison of complementary silicon diodes as well as GaAs diodes concerning power output and efficiency is given. The effects of doping profile, current density, temperature, and material parameters on the performance of these devices have been investigated and are summarized. Saturation effects which limit the efficiency and power output of these devices are described and optimum efficiencies which can be achieved for various doping profiles are given. A comparison between single-sided and double-drift diodes in both silicon and GaAs is also presented.

PLANAR GaN ELECTROLUMINESCENT DEVICE

Abstract: A GaN electroluminescent structure has been fabricated on a silicon substrate allowing for the construction of light-emitting diodes in the visible region on a planar surface carrying other silicon dependent devices.

Single heterojunction Pb1−x Snx Te diode lasers

Abstract: Single heterojunction diode lasers in the Pb1−xSnx Te alloy system have been fabricated by low‐temperature vacuum deposition of n‐PbTe on a p‐Pb0.88Sn0.12 Te substrate. The lasers have lower threshold current densities and operate cw at higher temperatures than homojunction devices in this material. At laser threshold the incremental diode resistance drops abruptly from 0.5 Ω to a series resistance limited value of 0.08 Ω, a previously unobserved effect in diode lasers which indicates very high internal quantum efficiency.

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.

Characteristics of tunable Pb1−xSnx Te junction lasers in the 8–12‐μm region

Abstract: The characteristics of tunable Pb1−xSnx Te (0.08⪝×⩽ lim ∼0.20) junction lasers are described. The lasers operate cw at liquid‐helium temperatures and for the above alloy compositions, the wavelength is in the 8–12‐μm region of the infrared. The devices are prepared by antimony diffusion into large p‐type vapor‐grown single crystals. Active region width, gain, and loss parameters are derived from measurements of the current density at the lasing threshold, efficiency, and cavity length dependence of the threshold current. Impurity diffused lasers favor oscillation in high‐order TE modes and some evidence of filamentary lasing was obtained from the device parameters together with a study of far‐field patterns. Results are presented which confirm the model of current tunability of these devices and provide data on refractive index and temperature dependence of the forbidden energy gap in these alloys. Finally, spectroscopic data are presented to show the present limitations and potential of the diode laser f...

Light emitting diode assembly

Abstract: A light emitting diode assembly which includes a light reflector formed at one end of, and as an integral part of a first electrical supply lead; a light emitting diode mounted within the reflector, one side of the diode junction being connected in electrical contact with the reflector which in association with the first lead provides a high heat sinking facility; and a second electrical supply lead one end of which is connected in electrical contact with the other side of the diode junction. The diode, the reflector and the said one end of the second lead are encapsulated in a bead of a light transparent material.

A new method of growing GaP crystals for light-emitting diodes

Abstract: A method named synthesis, solute diffusion (SSD) has been developed for growing compound semiconductor crystals, GaP in particular, for light-emitting diode (LED) use. The grown crystal is cylindrically shaped and is composed of fairly large-size grains. Growth rate is limited by the diffusion process of phosphorus in the gallium melt. The diffusion coefficient was obtained from the growth rate and found to be 8×10-5cm2s-1at 1100°C with an activation energy of 0.65 eV. Donor impurities, tellurium or sulfur, can be reproducibly incorporated from 3×1017to 4×1018cm-3, with segregation coefficients at 1150°C, 0.038 and 1.0, respectively. The quality of the grown crystals was observed to be exceptionally good, and the saucer-type pits were hardly observable in the crystal on modified AB etching. Highly efficient red-light-emitting junctions were reproducibly grown by only one single-layer-single-liquid-epitaxy process, in which zinc was doped from the vapor phase. A double-layer-single-epitaxy process, which we call "liquid epitaxial grown-in junction" process, was also developed and it produced highly efficient green LED's. The LED's grown on the SSD wafers have efficiencies up to 7.4 percent for red and 0.15 percent for green.

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 .

Method of manufacturing a light coupled monolithic circuit by selective epitaxial deposition

Abstract: There is disclosed a monolithic light coupled circuit and method of manufacture. In its elemental form, the monolithic circuit comprises a light or photo emitting diode and a light or photo sensitive diode formed integrally in a semiconductor chip with means for coupling the light from the photo emitting diode to the photo sensitive diode. Suitable leads are provided for connecting the photo emitting diode to an input circuit and the photo sensitive diode to an output circuit. In a more complex form, the monolithic structure may include a suitable discriminator detector circuit for the input and suitable driver amplifier circuit for the output.

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.

The elimination of tuning-induced burnout and bias-circuit oscillations in IMPATT oscillators

Abstract: IMPATT diode microwave oscillators suffer from the effects of low-frequency instabilities, which include excessive up-conversion of bias-circuit noise, bias-circuit oscillations, and diode burnout induced by tuning at the microwave frequency. These instabilities are particularly troublesome in GaAs diodes, although also present in both Ge and Si to a lesser extent. Moreover, these instabilities are more prominent in higher efficiency, higher power diodes, presenting a severe systems problem in the practical utilization of GaAs diodes at their highest power and efficiency levels. In this paper, it is shown that these instabilities may be eliminated in a systematic and well controlled manner with little or no loss in microwave power or efficiency. It is shown that the source of the unstable behavior is a low-frequency RF voltage-induced negative resistance which extends from dc to several tens, and perhaps hundreds, of megahertz, depending on the loaded Q of the microwave circuit. The negative resistance is an unavoidable fact of large-signal avalanche diode operation and is due to the rectification properties of the nonlinear microwave avalanche.

Luminescent solid state status indicator

Abstract: A luminescent solid state status indicator including at least first and second light emitting diodes of different colors which may be mounted on a single header. One side of each of the diodes is connected in common to one side of a source of energizing voltage subject to variation in magnitude. The other sides of the diodes are interconnected with the electrodes of a transistor which has one electrode connected to the other side of the DC energizing voltage. The transistor is adapted selectively to energize the first and second light emitting diodes to display colors corresponding respectively to discrete magnitudes of said energizing voltage.

Circuit for measuring and evaluating optical radiation

Abstract: The invention relates to a circuit for optically sensing coded data on a record medium and including a photosensitive transducing element such as a phototransistor. In order to render the circuit independent of background brightness variations, the load impedance of the transducing element includes one or more of series connected diodes which have an exponential characteristic curve, so that the voltage drop across the diode or diodes is proportional to the natural logarithm of the current flowing through the transducing element. The voltage difference resulting from sensing contrasting marks on the record medium thus depends only on the contrast in reflected light and not on the absolute value of the current in the transducing element.

CdSnP2–InP heterodiodes for near‐infrared light‐emitting diodes and photovoltaic detectors

Abstract: Heterodiodes have been prepared by liquid‐phase epitaxy of n‐type CdSnP2 from Sn solution onto p‐type InP. Electroluminescence is observed near 1.4 μ with internal quantum efficiencies of 10% at 77°K and 1% at room temperature. The photovoltaic response of typical diodes shows moderate quantum efficiencies (4–12%) in the near infrared (1.2–1.0 μ).

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.

High-power narrow-linewidth operation of GaAs diode lasers

Abstract: By utilizing a dispersive element in an external cavity, we find it possible for pulsed room‐temperature GaAs diodes to emit high output power (3 W) into a narrow linewidth (04 A) This narrow‐band output is continuously tunable over an ∼ 100‐A range with only a moderate variation in output power Significantly, these qualities are preserved even at high output power densities (3 × 106 W/cm2)

Bistable impedance states in MIS structures through controlled inversion

Abstract: Metal silicon‐nitride n‐p+ silicon diodes have been fabricated with I‐V characteristics similar to those of a four‐layer diode. Switching between the two impedance states, whose impedance levels differ by a factor of the order of 106, can be accomplished in less than 5 nsec. The impedance of the device is controlled by the presence or absence of the inversion layer of the MIS structure. Both impedance states require a nonzero conductance of the insulator.

Miniature diode-pumped Nd : YAIG lasers

Abstract: A miniaturized Nd : YAIG laser is described, in which a 5 × 0.45‐mm laser rod is end pumped by a single incoherent GaAs1−xPx light‐emitting diode. Laser threshold was achieved at room temperature in a pulse pumped mode of operation. The measured threshold optical power incident on the end of the laser rod was 19 mW at 24°C. Based on an extrapolation from known Ga1−xAlxAs diode performance, it is concluded that present technology can provide diode pumps to drive a miniature Nd : YAIG laser 2.4 times above threshold continuously at room temperature.

Mbe technique for fabricating semiconductor devices having low series resistance

Abstract: In order to fabricate by MBE semiconductor devices, such as junction lasers and light modulators or varactor and impatt diodes, having relatively low series resistance one or more of the following three steps are executed: (1) on the substrate a high conductivity buffer layer is first grown having the same conductivity-type as the substrate; (2) beginning with the high conductivity layer and until all semiconductor layers of the device are fabricated, the growth process is made to be continuous; and (3) the substrate is heated just prior to the growth of the high conductivity layer and under excess pressure of any element in the substrate which has a relatively high vaporization pressure and which tends to evaporate from the heated substrate. Preferably all three steps are performed.

AC Responsive led pilot light circuitry

Abstract: Disclosed is light-emitting electronic circuitry including a pair oppositely poled, parallel connected diodes, at least one of which is a light-emitting diode (LED); these diodes are serially connected to a capacitor between a pair of circuit AC input terminals. The capacitor provides the necessary AC voltage drop in series with these diodes when the circuitry is connected to a source of AC line voltage, and the minimum power and heat dissipated in this circuit make it especially well suited for small package pilot light applications.

Semiconductor thermal protection

Abstract: To prevent excessive semiconductor junction temperatures, thermally responsive impedances are mounted in heat transfer contact with the semiconductor device. Various combinations of impedances including positive and negative temperature coefficient thermistors, semiconductor diodes, transistors and thyristors are located in electrical series or shunt circuits which disable current flow through an adjacent semiconductor junction when the temperature thereof exceeds predetermined values. Load circuits in series with a thermally protected semiconductor device are protected from excessive load currents which might damage the load and/or the semiconductor device.