Showing papers on "Diode published in 1984"

High‐speed optical modulation with GaAs/GaAlAs quantum wells in a p‐i‐n diode structure

Abstract: A new type of high‐speed optical modulator is proposed and demonstrated An electric field is applied perpendicular to GaAs/GaAlAs multiple quantum well layers using a ‘‘p‐i‐n’’ diode doping structure of 4‐μm total thickness The optical absorption edge, which is particularly abrupt because of exciton resonances, shifts to longer wavelengths with increasing field giving almost a factor of 2 reduction in transmission at 857 nm with an 8‐V reverse bias The shifts are ascribed to changes in carrier confinement energies in the wells The observed switching time of 28 ns is attributed to RC time constant and instrumental limitations only, and fundamental limits may be much faster

Light-emitting diode assemblies and systems therefore

Abstract: A light string system is provided having a plurality of mono-color or bi-color light-emitting diodes electrically connected thereto. Each light-emitting diode has a generally elongated, hollow envelope mounted thereover, and the envelope is substantially filled with light-conducting optical spheres or even fragments. The envelope may be additionally filled with light-conducting epoxy, light-conducting liquid or light-conducting gas and sealed for improved light transmission and dispersion characteristics. The light-emitting diodes may include an improved base with light-emitting diode leads disposed approximately perpendicular to the axis of the envelope for bulb stability and for enabling the bulb to stand upright on the branches. Both the envelope and the optical spheres include light-conducting glass or plastic material. The spheres may be either hollow or spherical and may be of a uniform or a mixed size. Additionally, the balls may be large for stacking in single file within the envelope or centrifuged to the sides of the envelope with the center devoid of spheres. The light-emitting diodes may be adapted for use as Christmas tree strings and various AC and DC control circuits are provided for driving the light-emitting diodes, for blinking effects, for alternating between two colors, for alternating between three colors, for improving the length of the string and uniformity of intensity of illumination and the like. In a preferred embodiment of the Christmas tree string of lights, a master trunk line and a plurality of limb lines are provided. The limb lines plug into or connect to predetermined locations along the master trunk line for ease of assembly, replacement and the like. This string uses a series--parallel configuration wherein the upper and lower portion of the master trunk line and the individual light-emitting diodes within each limb line are connected in series while the limb line sets are connected in parallel with each other for enabling more lights to be illuminated with less power, for increasing the uniformity of illumination along the length of the string, and for minimizing light outage due to bulb burnout.

Organic‐on‐inorganic semiconductor contact barrier diodes. I. Theory with applications to organic thin films and prototype devices

Abstract: We discuss the properties of organic‐on‐inorganic (OI) semiconductor contact barrier diodes. A model for charge transport is developed which suggests that thermionic emission over the organic/inorganic contact barrier dominates at low current densities, whereas space‐charge effects dominate transport through the organic layer at high current densities. The effects of charge trapping in the organic layer are also considered. This model is applied to OI diodes using thin films of the prototypical aromatic compound; 3,4,9,10‐perylenetetracarboxylic dianhydride, (PTCDA) vapor‐deposited onto n‐ and p‐Si substrates. Several electrical and optical properties of PTCDA are investigated to provide a basis for analyzing the OI diodes. Both ohmic and space‐charge‐limited transport are observed in the PTCDA. We discuss mobility, transient response, and photoresponse of the thin‐film organic material. Also described are the general properties of organic‐on‐inorganic contact barrier diodes which employ PTCDA and related...

Passive mode locking of a semiconductor diode laser

Abstract: By using a GaAs/GaAIAs multiple-quantum-well sample as a saturable absorber in an external resonator, we have passively mode locked a GaAs laser to obtain pulses as short as 1.6 psec, the shortest pulses ever observed to our knowledge from a mode-locked diode laser in a regulator pulse train.

New infrared detector on a silicon chip

Abstract: We report a single-crystal Si-Ge structure which works as an efficient photodetector in the wavelength region of up to 1.5 µm. The multilevel structure is grown by molecular-beam epitaxy on an n-type 3-in silicon substrate and consists of the following layers: n+silicon (1000 A), n+Ge x Si 1 - x alloy (1800 A, graded in ten steps from x = 0 to x = 1 ), n+germanium (1.25 µm), undoped germanium (2.0 µm), and p+germanium (2500 A). Top three layers form a germanium p-i-n diode, which is removed from the Ge-Si interface by a buffer layer of high conductivity. An advantage of this structure is that its performance is insensitive to material defects in the buffer layers. Moreover, transmission electron microscopy shows that the density of dislocations introduced by lattice mismatch at the Ge-Si interface falls off with the separation from the interface. Our first experimental structures do exhibit the characteristics of a germanium p-i-n diode. The spectral response curves agree with those given in the literature for germanium, both at room and liquid nitrogen temperatures. For the incident light wavelength of 1.45 µm we have measured a quantum efficiency of 41 percent at T = 300 K. we believe that our approach opens an attractive possibility of fabricating complete infrared optoelectronic systems on a silicon chip.

The pinch rectifier: A low-forward-drop high-speed power diode

Abstract: A new concept for reducing the forward voltage drop of Schottky rectifiers without incurring excessive reverse leakage currents is introduced. In this concept, a junction grid is incorporated beneath the Schottky barrier to pinch off current flow during reverse blocking. Experimental results that demonstrate the capability to reduce the forward drop from 0.6 to 0.4 V without incurring an increase in leakage current are presented.

Charge injection transistor based on real-space hot-electron transfer

Abstract: We describe a new transistor based on hot-electron transfer between two conducting layers separated by a potential barrier. The mechanism of its operation consists of controlling charge injection over the barrier by modulating the electron temperature in one of the layers. This physical principle is different from those employed in all previous three-terminal amplifying devices-which are based either on the modulation of a potential barrier (vacuum triode, bipolar transistor, various analog transistors) or on the modulation of charge in a resistive channel (field effect transistors). In contrast to this, the present device can be compared to a hypothetical vacuum diode whose cathode has an effective electron temperature which is controlled without inertia by an input electrode ("cathode heater"). The device has been implemented in an AlGaAs/GaAs heterojunction structure. One of the conducting layers is realized as an FET channel, the other as a heavily doped GaAs substrate. The layers are separated by an Al x Ga 1 - x As graded barrier. Application of a source-to-drain field leads to a heating of channel electrons and charge injection into the substrate. The substrate thus serves as an anode and the FET channel represents a hot-electron cathode, whose effective temperature is controlled by the source-to-drain field. Operation of the charge injection transistor is studied at 300, 77, and 4.2 K. At 77 K the existence of power gain is demonstrated experimentally with the measured value of the mutual conductance g m reaching 280 mS/mm (at 300 K, g m ≈ 88 mS/mm). The fundamental limit on the device speed of operation is analyzed and shown to be determined by the time of flight of electrons across a high-field region of spatial extent ∼ 10-5cm. Practical ways of approaching this limit are discussed. The process of hot-electron injection from the channel is studied experimentally at 77 and 4.2 K with the purpose of measuring the electron temperature in the channel at different bias conditions. For not too high substrate bias the electron temperature in the channel is found to be proportional to the square of the heating voltage.

Current‐voltage characteristic of Ti‐pSi metal‐oxide‐semiconductor diodes

Abstract: The electrical characteristics of Ti‐pSi metal‐oxide‐semiconductor diodes have been studied as a function of temperature and of applied voltage, using conventional Schottky barrier capacitance‐voltage (C‐V) and current‐voltage (I‐V) measurements. The results show a strong deviation from those expected from thermionic emission and from the minority carrier injection theory for the current mechanism. Unlike other authors who proposed a multistep recombination‐tunneling mechanism, we have stressed that a model based on the inhomogeneity of the barrier height over the diode area predicts a temperature and voltage behavior of the I‐V characteristic similar to the recombination‐tunneling mechanism. The concept of inhomogeneity proposed by former authors is supported by Auger depth concentration profiles which show an intermixed region of Ti and Si. It is observed that the equilibrium semiconductor band bending exhibits a stronger temperature dependence than expected from the variation of the semiconductor Fermi level.

Process for producing a SiC semiconductor device

Abstract: A process for producing a SiC semiconductor device comprising growing a single-crystal film of SiC on a single-crystal substrate of Si and forming the structure of semiconductor device such as diodes, transistors, etc., on said SiC single-crystal film, thereby obtaining a SiC semiconductor device on a commercial scale.

Multi-spot modulator using a laser diode

Abstract: A multi-spot light modulator using a laser diode is disclosed in which a single light pulse from the laser diode generates a multi-spot image of a data pattern, each spot corresponding to an active bit of the data pattern. The ability of a pulsed laser diode to generate a narrow light pulse is used to image an acoustic wave corresponding to the data pattern without the normal degradation in resolution caused by the motion of the acoustic wave.

Pulsed power supply for an electrostatic precipitator

Abstract: A method and apparatus for generating a supply of pulsed power to an electrostatic precipitator where a residual collection field is maintained on the electrodes during interpulse periods while, in addition, high voltage pulses in excess of the residual are periodically impressed on the electrodes. The apparatus includes a series tuned circuit having a pulse forming section which creates a single damped cycle of oscillation to produce ionization current from a corona discharge electrode before unused power is returned to the pulse forming section. A blocking diode prevents the voltage on the precipitator from falling below the corona threshold voltage, and a series tuned trap circuit maintains the diode in conduction during pulsing to allow the return of unused energy.

Topics in the optimization of millimeter-wave mixers

Abstract: A user oriented computer program for the analysis of single-ended Schottky diode mixers is described. The program is used to compute the performance of a 140 to 220 GHz mixer and excellent agreement with measurements at 150 and 180 GHz is obtained. A sensitivity analysis indicates the importance of various diode and mount characteristics on the mixer performance. A computer program for the analysis of varactor diode multipliers is described. The diode operates in either the reverse biased varactor mode or with substantial forward current flow where the conversion mechanism is predominantly resistive. A description and analysis of a new H-plane rectangular waveguide transformer is reported. The transformer is made quickly and easily in split-block waveguide using a standard slitting saw. It is particularly suited for use in the millimeter-wave band, replacing conventional electroformed stepped transformers. A theoretical analysis of the transformer is given and good agreement is obtained with measurements made at X-band.

Monolithic planar doped barrier subharmonic mixer

Abstract: A single planar doped barrier diode is grown by the selective deposition of gallium arsenide using molecular beam epitaxy (MBE) in the center of a gallium arsenide dielectric waveguide member mounted on a ground plane. The waveguide member includes two portions which extend in opposite directions and terminating in respective metal to dielectric waveguide transition sections which are coupled to an RF input signal and local oscillator signal, respectively. The planar doped barrier diode operates as an intrinsic subharmonic mixer and accordingly the local oscillator signal has frequency of one half the input signal frequency. An IF output signal is coupled from the mixer diode to a microstrip transmission line formed on an insulating layer fabricated on the ground plane. Dielectric waveguide isolators are additionally included on the dielectric waveguide segments to mutually isolate the input signal and local oscillator signal. A monolithic form of circuit fabrication is thus provided which allows the planar doped barrier mixer circuit to be extremely small and the cost of mass producing such a circuit to be very economical.

Flexible safety belt with flashing light-emitting devices and alarm

Abstract: A flexible safety belt which may be easily worn about the waist of a pedestrian or runner is disclosed. The belt includes an arrangement for fastening the ends together and a plurality of light-emitting diodes disposed along the outer surface of the belt. A pair of oscillators having distinct different frequencies are connected to each of a respective pair of nodes between which all of the diodes are connected. The diodes are connected so that the lower frequency oscillator conditions a set of diodes to be flashed by the output of the higher frequency oscillator when the low frequency oscillator is in one state and the balance of the diodes to be flashed by the high frequency oscillator when the lower frequency oscillator output is in the opposite state. The electronic circuitry is all constructed on a flexible circuit board disposed within the hollow interior of the belt, with the circuitry also preferably including a separately controllable alarm means.

A precision CMOS bandgap reference

Abstract: The simple circuit uses naturally occurring vertical n-p-n bipolar transistors as reference diodes. Use is made of p-tub diffusions as temperature-dependent resistors to provide current bias, and an op-amp is used for voltage gain. Only two reference diodes, three p-tube resistors, and one op-amp are necessary to produce a reference with fixed voltage of -1.3 V. An additional op-amp with two p-tub resistors will adjust the output to any desired value. The criteria for temperature compensation are presented and it is shown that the properly compensated circuit can in principle produce thermal drift which is less than 10 p.p.m.//spl deg/C. Process sensitivity analysis shows that in practical applications it is possible to control the output to better than 2%, while keeping thermal drift below 40 p.p.m.//spl deg/C. Test circuits have been designed and fabricated. The output voltage produced was -1.3/spl plusmn/0.025 V with thermal drift less than 7 mV from 0/spl deg/C to 125/spl deg/C. Significant improvements in performance, at modest cost in circuit complexity, can be achieved if the op-amp offset contribution to the output voltage is reduced or eliminated.

Light for motor vehicles

Abstract: A light for motor vehicles is proposed, in particular a signal light for motor vehicles, with three-phase light-emitting diodes (10) or light- emitting diode chips (21) as light sources, which are arranged on or in a base-plate (20). In the proposed light, three-phase light- emitting diodes (21) serve as the light sources, these diodes being white or transparent when in the unexcited state and emitting light of at least two different colours, for different lighting and/or signalling functions, it being possible to activate these functions, according to the signal colour desired, by applying different voltages.

Semiconductor device with electrostatic discharge protection.

Abstract: An input protection circuit for an MOS device uses a thick-oxide transistor connected as a diode between a metal bonding pad and ground. The channel width of this transistor is chosen to be sufficient to withstand large, short-duration current spikes caused by electrostatic discharge. More important, the spacing between a metal-to-silicon contact to the drain of this transistor and the channel of the transistor (where heat is generated), is chosen to be much larger than usual so the metal of the contact will not be melted by heat propagating along the silicon surface during the current spike due to ESD. This spacing feature also applies to circuits for output pads, or circuits using diode protection devices.

Electroluminescent display drive system

Abstract: A resonant mode energy recovery circuit is disclosed for supplying drive pulses to an electroluminescent (EL) display arranged as a matrix of pixels addressed by a plurality of column and row electrodes. An external inductor is used to alternately store and supply energy from the column electrodes of the EL display which has an impedance equivalent to an array of capacitors and resistors. Switching transistors and diodes are used to start and stop the resonant current flow at 1/4 wavelength intervals of the resonant frequency of the resonant tank formed by the external inductor and the array capacitors coupled to the column electrodes in order to form the pulses required to address the columns of the matrix. Switched current sources are used to start and stop nonresonant current flow to form the refresh and write pulses used to form the pulses required to address the rows of the matrix. Together, the pulses applied to the columns and rows of the matrix provide the high voltage necessary to light the EL pixels while minimizing the address time and power required to operate the EL display.

Optical-level shifter and self-linearized optical modulator using a quantum-well self-electro-optic effect device.

Abstract: We demonstrate an optical-level shifter and a modulator whose transmission varies linearly with drive current, both based on a new, negative-feedback mode of operation of the recently discovered quantum-well self-electro-optic effect device. The system is compatible with both laser diodes and low-power semiconductor electronics and is applicable in both analog and digital optical processing. An extension of the system gives inverted, linear modulation of a coherent beam by an incoherent light source.

The integration of bypass diodes with terrestrial photovoltaic modules and arrays

Abstract: Bypass diodes are often required to limit the potential for reverse voltage 'hot-spot' heating in high voltage arrays or in arrays that undergo periodic operation near the short-circuit point. In addition, when properly applied, bypass diodes can minimize the effect of shadowing and various internal module failures on the array energy output. This paper discusses the mechanical and electrical integration of bypass diodes beginning with the array-level considerations which influence the selection of an implementation approach. Concepts for the mounting of these diodes, both internally within the module encapsulant and externally to the exposed rear surface of the module, are described. Factors affecting the reliability of bypass diodes, including the control of junction temperature through adequate heat sinking and the derating of reverse voltage, are discussed.

High-speed low-loss p-n diode having a channel structure

Abstract: A p-n diode having a channel structure (static shielding diode, SSD) is proposed to increase the reverse blocking voltage of a low-loss high-speed p-n diode. It is shown by numerical analysis and experiment that a low-loss, high-speed SSD with high blocking capability can be realized by surrounding the p-layer and a portion of the n-layer with a highly doped p+-layer. In this method, the blocking voltage can be increased by a factor of 2 to 3.5 without sacrificing the low forward voltage drop and fast reverse recovery. The SSD with a 0.81-V forward voltage drop at 80 A/cm2, a 180-V blocking voltage at 150°C, and a 87-ns reverse recovery time can be fabricated.

Semiconductor package with internal heat exchanger.

Abstract: An internally cooled semiconductor package including a wafer-like semiconductor body (diodes 12) with at least two electrical elements, one at a relatively flat surface (18) of the body. A wall (20, 22) if high electrical and heat conductive material abuts the flat surface of the semiconductor body to be in good heat conductive relation therewith and in electrical contact with the same. A fluid flow heat exchanger (10) is on the other side of the wall in heat exchange relation therewith and along with the wall and other components serves to encapsulate the semiconductor.

Semiconductor device comprising a dmosfet

Abstract: A semiconductor device is disclosed in which the anode and cathode of a diode (D3) are connected respectively to the source (S) and drain (D) of the MOSFET (QM1). The diode (D3) has a set forward voltage drop lower than that of a parasitic diode (D1) formed by the junction between a channel base region (14a, 14b) and a drain region (12) constituting the MOSFET (QM1).

A Broad-Band, Ultra-Low-Noise Schottky Diode Receiver from 80 to 115 GHz Diode

Abstract: A cryogenic 3-mm receiver has been developed which fully utilizes the low-noise potential of Schottky diodes by approaching the shot-noise limit within 10 percent. With a broad-band mixer design which properly terminates the input sidebands and reactively terminates the second harmonic of the local oscillator and its sidebands, the double sideband (DSB) mixer noise temperature is 35 K in the best case. This design has given an average DSB receiver noise temperature of 75 K over the 80 to 115-GHz band with a best noise temperature of 62 K.

Driver for differential signal transmission

Abstract: A driver for transmitting a digital differential signal along a transmission line during a packet time and not during an idle time while maintaining a constant common voltage between the transmission line and ground throughout the packet and idle time periods. A driving circuit and its drive controller in the driver and respectively formed from paired matched transistors which function as on-off switching circuits and have a common emitter load acting as a constant current source. A collector of a first transistor in the drive controller is connected to the common emitter of the driving circuit and a collector of a second transistor in the drive controller is respectively connected to the collectors of the pair of transistors of the driving circuit through respective matched diodes. During the idle time, the driving circuit is cut off by the first transistor being cut off, and the second transistor carries collector current, which is separated into halves, through respective matched collector resistors in the driving circuit and the matched diodes. The voltage on each collector in the pair of transistors in the driving circuit becomes the mean value of a high and a low voltage levels produced during the packet time. The constant common voltage can be obtained from this mean voltage by using emitter followers. Matched transistors can be used instead of the matched diodes.

Optoelectronic integrated device with light amplification and optical bistability

Abstract: With the use of InP compound and InGaAsP alloy semiconductors, integrated devices have been fabricated in which a double heterojunction light-emitting diode is integrated onto the collector portion of a heterojunction phototransistor. The following results have been achieved in experiments with 1.15-µm wavelength light. The device amplifies the light. The maximum gain was 11.2 and the maximum differential was 31. The device is optically bistable. The optical bistability with positive gain was operated with at most 40-µW input light. The device exhibits a function similar to a light-activated thyristor and possesses a light unidirectional function. The unidirectionality measured was 16.5 dB.

Electric field probe

Abstract: An electric field probe array including several dipole probes, each including a diode connected between two conductors with the diodes being collectively connected to at least two probe terminals. Also disclosed is a system for heating a target with electromagnetic radiation that includes a central control unit, a source coupled to the control unit with the source generating the electromagnetic energy at a frequency and power in response to the control unit, a radiation apparatus coupled to the source for transferring the electromagnetic energy from the source to the target and input circuitry connected to the control unit for indicating the status of the target whereby the operation of the system is controlled by the control unit as a function of the target's status. The input circuitry includes several electric field probe arrays where each electric field probe array includes several individual diode probes that each include a diode connected between two conductors with the diodes collectively connected to electric field probe array terminals which are connected to the input circuitry.

Photoconductive power switch

Abstract: A photoconductive power switch capable of producing electrical pulses of at least 10 amperes and 100 volts at switching speeds of one nanosecond or less is disclosed. The photoconductive power switch comprises a wafer of high resistivity semiconductor material selected from Group III and Group V compounds, preferably indium phosphide. A pair of electrodes are mounted on the wafer and are spaced apart to form a gap. A diode laser is provided for illuminating the gap with light having a wavelength of from about 200 to about 850 nanometers at an intensity of at least 50 picojoules.

Numerical Studies of Charge Collection and Funneling in Silicon Device

Abstract: The results of a recently completed numerical study of charge and current transients following passage of ionizing particle through N+P diodes, and its dependence on excess carrier density, track and device length, are discussed.

Display comprising light-emitting diodes and a method and an installation for its manufacture

Abstract: A display incorporating light-emitting diodes, comprising a reflector which is formed in a holder. A light-emitting diode is mounted in the holder and projects into the reflector through an opening. The light-emitting diode is attached in the opening with the diode walls snugly abutting against the edges of the opening. The invention also relates to a method of manufacturing the display comprising light-emitting diodes and an installation to perform the method. Each diode is provided with two connections protected by the holder. The holder consists of surface-treated sheet metal, preferably anodized aluminum. The reflector is bowl-shaped and semispherical. Owing to the reflector a bundle of aligned beams of light is emitted from the light-emitting diode.