Showing papers on "Diode published in 1968"

Determination of Threshold Failure Levels of Semiconductor Diodes and Transistors Due to Pulse Voltages

Abstract: Theoretical predictions of circuit failure in an Electromagnetic Pulse (EMP) environment require a knowledge of failure levels for each component of the circuit due to surge voltages or currents. For most circuits, the semiconductor devices are the weakest elements with respect to such failure. This paper presents the results of an extensive experimental program to determine pulse power failure levels of semiconductor junctions. Approximately 80 different types of silicon diodes and transistors were studied with variations in junction areas from 10-4to 10-1 cm2 and with widely varying junction geometries. Power levels of up to two kilowatts, with time durations of 0.1 to 20 microseconds, were applied to semiconductor junctions in both forward and reverse polarity modes. A semi-empirical formula, based on experimental data and on a simple thermal failure model is given. From the formula one can make order-of-magnitude estimates of the failure level as a function of pulse length for many silicon diodes or transistors whose junction area is known.

Silicon schottky barrier diode with near-ideal I-V characteristics

Abstract: Metal-semiconductor diodes with near-ideal forward and reverse I-V characteristics have been fabricated using PtSi contacts and diffused guard rings. Typically, for a device with an area of 2.5 × 10−6 cm2 made on an n-type (111) oriented, 0.35 ohm-cm silicon epitaxial substrate, the forward current follows the expression I f = I s exp (qV/nkT) over eight orders of magnitude in current with I s = 10−12 A and n = 1.02. The reverse breakdown is sharp and occurs at the theoretical breakdown voltage of p+ n silicon junctions of the same n-type doping. The premature breakdown observed in nearly all previous Schottky barrier diodes has been shown to be caused by electrode sharp-edge effects. Besides giving sharp breakdown voltage, the guard ring also eliminates anomalously high leakage currents, yet still retains the fast recovery time characteristic common to other Schottky barriers. Typically, the recovery time measured at 10 ma is less than 0.1 ns, the resolution of the measurement.

Frequency mixing in the infrared and far‐infrared using a metal‐to‐metal point contact diode

Abstract: Metal‐to‐metal point contact diodes were used to obtain the 54‐GHz beat notes between two adjacent 10.6‐μ CO2 laser transitions. The speed of the diodes in the far‐infrared is at least 1000 GHz. This was tested with a 337‐μ HCN laser.

Circuit for reducing stray capacity effects in transformer windings

Abstract: A transformer charging system that provides a highly efficient operation and that substantially eliminates switching transients. The high voltage or secondary winding of the transformer as well as the primary winding in some arrangements, is divided into segments which are isolated from each other by unidirectional current conductive devices such as diodes. For charging a load coupled to the secondary winding, current pulses are repetitively applied to the primary winding from the power source with the flyback voltage resulting from the pulse terminations causing current to flow through the diodes. The diodes allow the stray capacitance associated with each segment to initially charge but prevent them from discharging between the repetitive operations, which would cause additional flow of primary current and dissipation losses.

High-efficiency oscillations in germanium avalanche diodes below the transit-time frequency

Abstract: Pulsed operation of Ge avalanche diodes has produced oscillations with efficiencies exceeding 40 percent at frequencies of 2-3 GHz. Computer simulation of diode and circuit behavior has provided an explanation for the observed results.

Millimeter-Wave Integrated Circuits

Abstract: Monolithic millimeter-wave integrated circuits have been designed and fabricated on semi-insulating GaAs substrates using microstrip transmission lines. Circuits using hybrid techniques have also been constructed on quartz and ceramics. This paper shows that microstrip-line integrated circuits are feasible at millimeter-wave frequencies. Circuit functions have been constructed and tested in the 25- to 100-GHZ range. The loss in microstrip line on semi-insulating GaAs was found to be less than 0.3 dB//lambda/. Couplers from waveguide to microstrip have been made with transmission losses less than 0.5 dB. Monolithic integrated detectors showed 5-dB better sensitivity than a 1N53 diode in a Philips detector mount. Monolithic diodes delivered 1.5 mW at 28 GHz. The results are encouraging and a fully monolithic integrated receiver is under development.

LONG‐WAVELENGTH INFRARED Pb1−xSnxTe DIODE LASERS

Abstract: Diode lasers with emission wavelengths as long as 28 μ have been fabricated using Pb1−xSnxTe with x up to 0.27. Properties of laser diodes at 77°K and 12°K have been measured for a number of compositions in the range 0.15 ≤ x ≤ 0.27. The vapor growth and annealing‐diffusion steps were performed in a special quartz ampoule which remained sealed throughout the process. Threshold current densities were dependent on diode surface conditions and could be reduced by at least 50% by etching.

Influence of bulk and surface properties on image sensing silicon diode arrays

Abstract: Silicon diode arrays for use as the electron-beam accessed target in camera tubes for the Picturephone® visual telephone set have been fabricated and their properties evaluated. These targets offer significant advantages over the antimony trisulfide target commonly used in vidicon-type tubes. But there are certain potential limitations which must be dealt with in developing a silicon target. Three of its critical requirements are adequate sensitivity to visible light, low dark current, and junction uniformity and freedom from defects across at least 300,000 diodes per square centimeter. Sensitivity to visible light is expressed here by the efficiency for conversion of incident photons to electrons in the read-out circuit. Conversion efficiencies exceeding 50 percent in the visible region have been achieved by oxidizing or by diffusing phosphorus into the light-receiving surface to reduce the surface-recombination velocity. Diode leakage currents of ≦1 × 10−13 A per diode are required, and are obtained for target voltages up to about 5 to 7 V. Surface generated current dominates in the 8-μ diameter diodes of the array, but this component of current can be reduced substantially by use of (100) surfaces or by hydrogen annealing. Visible defects in a picture can result from leaky diodes or oxide pinholes which cause bright spots, and diodes covered by oxide which cause dark spots. Our best targets show a video display with only a few defects; processing must be improved to eliminate defects completely.

Method for diffusing an impurity substance into silicon carbide

Abstract: Impurity ions are accelerated under an irradiation condition of ordinary temperature or relatively low temperature and injected into silicon carbide from its surface. The injected silicon carbide is annealed in a temperature range from 1,600* to 1,200* C. to obtain a PN junction and a luminescent diode based on the PN junction is thereby prepared.

Space-charge-induced negative resistance in avalanche diodes

Abstract: With a realistic and accurate model and the use of numerical techniques to solve the diode equations, it is shown that certain p+-n-n+diodes exhibit a static negative resistance that is due to space-charge effects. The magnitude of this resistance and the value of current density at which negative resistance appears depend on several device parameters. The dependence of the diode characteristics on these device parameters is presented for several examples. The characteristics of these devices at high frequencies are also discussed, and the possibility of high-powers high-efficiency operation as an oscillator is briefly treated.

A large signal analysis of IMPATT diodes

Abstract: This paper presents results on RF power output and efficiency of IMPATT oscillators obtained from a large-signal model of these devices. The results are obtained from a closed-form solution of the nonlinear equations describing a Read-type IMPATT diode. The closed-form solution is obtained by assuming a short transit time through the drift region compared to the RF period. The solution is used to obtain the large-signal diode impedance. The analysis shows that the power output of an IMPATT diode depends strongly on the series load resistance presented to the active part of the diode and that the change in diode reactance with increasing bias current also depends on the series resistance. Plots of power output as a function of frequency, bias current, and load resistance are presented. Frequency tuning of the oscillator through current variation is also discussed. Experimental results are presented and compared with the theoretical ones wherever possible. The results lead to an improved understanding of such oscillators and are extremely useful in optimizing their performance and determining their limitations.

Carrier lifetime measurement of a junction laser using direct modulation

Abstract: A carrier lifetime measurement under lasing conditions using microwave techniques is reported. The direct modulation characteristic of a junction laser is analyzed, based on the rate equations, and a resonance-like phenomenon of the modulated output is calculated at a fixed frequency determined by the parameters of the junction diode. This frequency occurs just before the modulation cutoff frequency of the diode. The minority carrier lifetime in the active region of the junction laser is expressed in terms of this frequency and other parameters. A modulation experiment was performed using a microwave frequency modulated bias pulse current. The resonance-like phenomenon was confirmed experimentally and the carrier lifetime was determined from the analysis presented here.

Continuous microwave oscillations in GaAs junction lasers

Abstract: Microwave oscillations produced by continuously operating GaAs stripe geometry junction lasers are reported here for the first time. These oscillations have been measured both in the light output of the diodes and in the dc current applied to the laser connections. The frequency of the oscillation lies in the 0.5- to 3.0-GHz range and depends strongly on current and temperature. The frequency typically increases with increasing current at a rate of 15 to 20 MHz/mA and decreases with increasing temperature at 100 to 150 MHz/°K. Introduction of an external microwave signal locks the frequency of the oscillation and reduces the oscillation width from 10 MHz to the external signal width. The frequency of oscillation agrees with a theory of intensity fluctuations in lasers based on the rate equations.

Shot noise in silicon Schottky barrier diodes

Abstract: Noise measurements have been performed on forward and reverse-biased silicon Schottky barrier diodes. Measurements were performed in the frequency range of 100 Hz to 50 kHz. Apart from excess noise observed for some diodes in a portion of this frequency range, the noise for the diodes was found to be in excellent agreement with shot-noise theory. Some refinements of the shot-noise theory have been considered, but the difference between the refined and the simple theories was not resolvable in our measurements. A useful noise-measurement technique is described.

Negative resistance and filamentary currents in avalanching silicon p + -i-n + junctions

Abstract: Space-charge effects in avalanching p+-i-n+diodes give rise to a current-controlled bulk negative resistance. It is shown that this negative resistance gives rise to an instability which tends to lead to the formation of current filaments. A steady state can be found in which the generation of carriers in the filament by impact ionization is balanced by radial diffusion of carriers. We present the results of approximate numerical calculations of filament current-density profiles and total filament current as a function of applied voltage. The total filament current is a decreasing function of the applied voltage; thus, the diode exhibits a quasistatic negative external resistance. It is suggested that this negative resistance may be used to interpret observed sub-transit-time oscillations of p+-i-n+structures.

Laser encoding of diode arrays

Abstract: A method and means for encoding a silicon-on-sapphire diode array by bombarding selected diodes or diode connections with a pulsed laser beam to burn away chosen silicon and metallization areas. Removal of these areas from the diode matrix constitutes an encoding process by elimination of the selected connection and/or diode.

Temperature and current distribution in an avalanching p-n junction

Abstract: The temperature and current distribution in an avalanching Si p - n junction have been calculated numerically by assuming a linear variation of breakdown voltage with temperature and a constant space charge resistance. As the diode radius is increased the temperature variation across the diode decreases while the current variation increases. For a 60 μ radius junction, the current density at the edge is about a factor of 2 larger than the current density at the center; for a ring diode with the same area the maximum current variation between center and edge is ≈ 20 per cent.

INTERNAL Q SWITCHING IN GaAs JUNCTION LASERS

Abstract: Internally Q‐switched light pulses have been obtained from junction lasers. Narrow bursts of light (<400 psec wide) were detected immediately after the termination of the injection current pulse. The effect persists for a wide variation in the length of the current pulse, from less than 2 nsec to several μsec. The internal absorption losses controlling Q switching are strongly dependent on both temperature and current. The effect is only seen in diodes with very low transition temperatures (Tt) between the regions of short and long stimulated emission delay times.

High-efficiency CW impatt operation

Abstract: CW room-temperature operation of Ge Impatt diodes with efficiencies as high as 43 percent in the 400 to 1000 MHz frequency range has been achieved. In this low-frequency, high-efficiency mode, the dc voltage drop across the diode is observed to decrease significantly.

The electrical characteristics of nZnSe—pGe heterodiodes†

Abstract: The forward and reverse current-voltage characteristics and reverse-biased capacitance are described for the nZnSo-p+ Ge emitter-base diodes of heterojunction transistors The forward diode current flow involves essentially electron injection into the Go together with loss-mechanisms of recombination of injected electrons through interface states and, probably, electron capture into ZnSo traps followed by tunnelling into interface states In the junctions that have been fabricated, the current-voltage characteristics are dominated by the high resistivity bulk ZnSo in series with the junction, resulting in space-charge-limited flow The reverse junction characteristics demonstrate semi-saturation, avalanche multiplication, and negative resistance The junction capacitance is strongly frequency dependent duo to the presence of relatively deep traps, and both abrupt and linearly graded junctions have boon observed, depending on the growth technique

Diffused diodes in silicon-on-sapphire

Abstract: The forward and reverse I–V characteristics of diffused diodes made in silicon grown epitaxially on sapphire have been measured. Silicon of doping density 4 × 10 15 to 6 × 10 17 /cm 3 p -type and 2 × 10 15 to 10 18 /cm 3 n -type have been used in these experiments. The forward conduction current of all diodes tested varied as exp ( qv /> nkT ) with n ≈ 1.7. Minority carrier lifetimes of the order 10 −10 sec have been inferred from the I–V data. The reverse currents were somewhat larger than predicted on the basis of currents generated in the space charge region but were reproducible from diode to diode. The temperature dependence of the diode currents was measured from room temperature to 200°C and followed the theoretical prediction. The variation of minority carrier lifetime with film thickness was measured, and the lifetime was found to increase as the silicon became thicker. Diodes produced by diffusion through the silicon to the silicon-sapphire interface were found to have minority carrier lifetimes about an order of magnitude lower than diodes not diffused to the bottom interface.

Reverse‐Biased Gallium Phosphide Diodes as High‐Frequency Light Modulators

Abstract: Reverse‐biased gallium phosphide diodes have been successfully operated as high‐frequency intensity and phase modulators of light at room temperature. The high‐frequency modulation is fundamentally limited by the series resistance and the capacitance of the diodes. Cutoff frequencies as high as 7 GHz have been measured. Diode capacitance, typically less than 7 pF at the operating point, and driver impedance determine the broad‐band characteristic. Intensity modulation measurements have been performed up to 500 MHz. The power consumption per MHz bandwidth for 40% intensity modulation was 2.7 mW for a diode only 0.7 mm long. A diode of 1.5 mm length used as a phase modulator needed only 1.5 mW of power per MHz bandwidth for a modulation index of 1 rad at a wavelength of 0.633 μ. This latter value corresponds to an intensity modulation depth of over 80%.

Semiconductor circuit devices using insulated gate-type field effect elements having protective diodes

Abstract: Insulated gate-type field effect transistors used in capacitive memory circuits and having protective diodes for protecting the insulating films below the gate electrodes from electrical breakdown, in which parasitic transistor action which might be caused by minority carriers injected into semiconductor substrates by noise signals applied to the protective diodes are eliminated by means for suppressing the injection of minority carriers or by means for preventing injected minority carriers from reaching the drain regions of the field effect transistors.

Degradation of GaAs injection devices

Abstract: The degradation characteristics of GaAs tunnel diodes, electroluminescent diodes, and injection lasers were investigated in detail. The degradation of all devices is manifested by an increase in excess current (tunneling via interband states). The rate of increase of the excess current is proportional to the injection current density for all, both at 78°K and in the 300°K region. The radiation output is proportional to the injection current and the proportionality factor does not change with the degradation. Thus, although degradation occurs, the quantum efficiency is not reduced when the injection current is not held constant during ageing. The degradation is found to be a bulk effect. The results are consistent with a model in which energy released by the reconbination of injected electrons creates Frenkel defects, and the excess current results from tunneling via the interband states associated with these defects. Other characteristics of degradation, such as the decrease in peak current for tunnel diodes, the decrease in capacitance and the increase in built-in voltage in lightly doped electroliminescent diodes, and the increase in the threshold current in lasers are explained in terms of the model.

Injection‐Laser Far‐Field Patterns with Gaussian Profiles in the Junction Plane

Abstract: Far‐field patterns from GaAs junction lasers with stripe contacts about 13 μ wide have been studied. At room temperature, more than 80% of the diodes have approximately Gaussian intensity profiles along the junction plane. Intensity measurements show that the profiles are stable for currents exceeding threshold by 60% in some diodes. These experimental results indicate that the lasers oscillate predominantly in the lowest‐order mode. Previously, with 50 μ stripe widths it was impossible to predetermine the dominant mode or to insure its stability for current variations greater than about 5%. In contrast to the symmetric behavior along the junction plane the radiation patterns perpendicular to the plane are asymmetric. Infrared photographs show a major lobe along with several minor lobes, the latter always appearing on the n side of the junction plane. The main features of the asymmetry are essentially the same for similarly fabricated diodes. Differences are found in the intensity distributions or widths of the minor lobes.

External cavity coupling and phase locking of gallium arsenide injection lasers

Abstract: The techniques involved in phase locking large multi-element junction laser arrays will be described. Specific mention is given to external cavity coupling, laser uniformity, physical dimensions, and array configuration. As a result, it has been found that a far more ideal beam pattern can be obtained from large diffraction-limited diodes than from a linear array of small ones. A coupled five-element array of 25-mil-wide units operated at-30°C has emitted 19 watts of peak power in a set of common modes.

Transient temperature distribution in diode lasers and the time duration of the output pulse at 300&#176;K

Abstract: A relatively simple method for obtaining the approximate temperature profile across a GaAs diode laser during a short, rectangular current pulse is described. The method, based on consideration of the thermal diffusion of an initially heated slab parallel to the p-n junction, allows the inclusion of the thickness and distribution of more than one heat source. Results are valid for short times up to a maximum corresponding to a thermal diffusion length L = \sqrt{kt} , where k is the thermal diffusivity, equal to the junction depth. Numerical results are given for GaAs diodes operated at room temperature and some of the assumptions are verified experimentally. Finally, the results are used to estimate the shape and duration of the light output pulse in terms of threshold and drive current.

Millimeter-Wave Integrated Circuits

Abstract: Monolithic millimeter-wave integrated circuits have been designed and fabricated on semi-insulating GaAs substrates using microstrip transmission lines. Circuits using hybrid techniques have also been constructed on quartz and ceramics. This paper shows that microstrip-line integrated circuits are feasible at millimeter-wave frequencies. Circuit functions have been constructed and tested in the 25- to 100-GHz range. The loss in microstrip line on semi-insulating GaAs was found to be less than 0.3 dB/ /spl lamda/. Couplers from waveguide to microstrip have been made with transmission losses less than 0.5 dB. Monolithic integrated detectors showed 5-dB better sensitivity than a 1N53 diode in a Philips detector mount. Monolithic diodes delivered 1.5 mW at 28 GHz. The results are encouraging and a fully monolithic integrated receiver is under development.