Showing papers on "Diode published in 1986"

Extraction of Schottky diode parameters from forward current-voltage characteristics

Abstract: It is shown that by using the forward current density‐voltage (J‐V) characteristics of a Schottky diode, a plot of d(V)/d(ln J) vs J and a plot of the function H(J) vs J, where H(J)≡V−n(kT/q)ln(J/A**T2), will each give a straight line. The ideality factor n, the barrier height φB, and the series resistance R of the Schottky diode can be determined with one single I‐V measurement. This procedure has been used successfully to study thermal annealing effects of W/GaAs Schottky contacts.

Zero-voltage switching technique in DC/DC converters

Abstract: A novel resonant switch operating under the principle of zero-voltage switching is presented. In contrast to the zero-current switching, this technique eliminates the switching loss and dv/dt noise due to the discharging of MOSFET's junction capacitances and the reverse recovery of diodes, and enables the converters to operate at yet higher frequencies.

Laser Doppler velocimeter using the self-mixing effect of a semiconductor laser diode.

Abstract: A laser Doppler velocimeter (LDV) using a semiconductor laser diode (LD) with its self-mixing effect has been developed. A Doppler signal, caused by mixing a returned wave with an originally existing wave inside the LD, is detected with a photodetector in the LD package; it is also picked up from the variation of the LD driving voltage. When the returned light is weak enough, it confirms that there is no change in the single-mode oscillation and its spectral width of the LD. A LDV of this type is compact enough for many applications.

Distance measurement by the wavelength shift of laser diode light

Abstract: This paper proposes a method for measuring distance larger than the wavelength of light with an interferometer using a laser diode. This method uses the fact that the wavelength of the emitted light of a laser diode varies in proportion to the diode’s injection current. The phase difference between the two interfering beams varies due to the sinusoidal variation of wavelength. The variation of the phase difference is detected by the optical heterodyne method. The magnitude of the variation is proportional to the measuring distance and the light wavelength shift. If the wavelength shift is known, a distance larger than the wavelength can be obtained from measurement of the phase variation. This method is a kind of multiwavelength interferometry using a single light source. We have done some fundamental experiments with this method and have confirmed its applicability to practical applications.

Ornamental light display apparatus

Abstract: Ornamental and decorative light display utilizing LEDs constructed of two or more individual diodes. Each diode or portion of a diode is alternately selected and energized at a sufficient frequency that colors can blend to produce another color. The system provides for an extremely large configuration of LEDs to be driven at a low average power and at the same time to allow the user to select individual lights to be constantly illuminated or flash in response on oscillating voltage source or allow multicolored patterns to be generated using bicolor LEDs.

Selectively formable vertical diode circuit element

Abstract: A programmable low impedance interconnect diode element is disclosed having a lower electrode formed of a semiconductor material of a first conductivity type covered by an insulating dielectric layer which may be in a preferred embodiment comprised of an initial layer of silicon dioxide, a second layer of silicon nitride and a third layer of silicon dioxide, covered by a layer of semiconductor material of a second conductivity type A programmable read only memory array and a programmable logic array comprising a plurality of the above-described cells are also disclosed

On the current transport mechanism in a metal—insulator—semiconductor (MIS) diode

Abstract: The current transport mechanism in an MIS-tunnel diode has been studied by considering both the process of tunneling and the effect of pinholes in the insulating layer. It has been shown that in order to explain the experimental J - V characteristics of MIS-diodes, presence of a thin interfacial layer of thickness δ p within the pinholes should be considered. From an analysis of the tJ - V and C - V characteristics, a method has been suggested for the estimation of the value of δ p . The values of interface trap density and barrier height for the MOS-part of the diodes are also calculated. The dependence of barrier height on oxide thickness for the diodes is found to obey the barrier height model of Cowley and Sze.

Room temperature cw operation of InGaP/InGaAlP visible light laser diodes on GaAs substrates grown by metalorganic chemical vapor deposition

Abstract: Room‐temperature cw operation for InGaP/InGaAlP double heterostructure (DH) laser diodes on GaAs substrates was achieved for the first time. The DH wafers were grown by low‐pressure metalorganic chemical vapor deposition using methyl metalorganics. A lasing wavelength of 679 nm and a threshold current of 109 mA at 24 °C were obtained for an inner stripe structure laser diode with a 250‐μm‐long and 7‐μm stripe geometry. The laser operated at up to 51 °C. The characteristic temperature T0 was 87 K at around room temperature. The lowest threshold current density, 5.0 kA/cm2, was obtained with a 20‐μm stripe width laser diode under room‐temperature pulsed operation.

Semiconductor device with protective means against overheating

Abstract: A semiconductor substrate has a power region and a control region. The control region is located in the center portion of the substrate, and the power region surrounds the control region and is separated therefrom. A vertical type, MOS transistor, i.e., an active semiconductor element, is formed on the power region. An insulation film is formed on part of the control region. A polycrystalline silicon diode, which functions as a heat-sensitive element, is formed on the insulation film. A control section comprising a lateral type, MOS transistor is also formed on the control region. The lateral type, MOS transistor is connected to receive a signal form the polycrystalline silicon diode. Further, a polycrystalline silicon resistor, which determines a circuit constant, is formed on the insulation film. The MOS transistor protects the active semiconductor element in response to a signal supplied from the heat-sensitive element showing that the temperature of the semiconductor substrate has risen above a predetermined value. For example, the active semiconductor element may be disabled until the detected temperature drops below a predetermined value.

Two dimensional laser diode array

Abstract: A two dimensional laser diode array is disclosed for use in optical data storage consisting of rows and columns of individual lasers diodes, each one having a separate collimating lens. The array is imaged down onto an optical recording medium which is moving relative to the image of the array in order to generate scanning. The diodes in the array are staggered in the direction perpendicular to the scanning direction to achieve an apparent spacing lower than the actual spacing.

Surface Damage on GaAs Induced by Reactive Ion Etching and Sputter Etching

Abstract: surface damage induced by reactive ion etching (RIE) using various gases is compared with sputter etching using inert gases. Anisotropic etching of with minimal surface damage can be obtained with most of the RIE conditions used. Sputter etching using inert gases introduces substantial damage on the surface, and the degree of damage is inversely proportional to the ion mass. In addition, we have found that the damage induced by Ar sputter etching can be greatly reduced by the introduction of reactive gases during etching. Recovery of the diode characteristics is observed after removing 500A of the etched surface using wet chemical solution or by removing 200A of the etched surface using RIE in at 30V.

Integrated quantum well self-electro-optic effect device: 2 × 2 array of optically bistable switches

Abstract: We demonstrate 2×2 arrays of optically bistable devices with very uniform optical characteristics. They are fabricated from an integrated self‐electro‐optic effect device structure consisting of a quantum well p‐i‐n diode grown in series with a load photodiode. Operating power can be optically controlled with a separate beam between ∼40 pW and >470 μW with associated switching times of ∼10 s and <2 μs.

Junction termination extension for near-ideal breakdown voltage in p-n junctions

Abstract: Extremely high breakdown voltages with very low leakage current have been achieved in plane and planar p-n junctions by using an ion-implanted junction extension for precise control of the depletion region charge in the junction termination. A theory is presented that shows a greatly improved control of both the peak surface and bulk electric fields in reverse biased p-n junctions. Experimental results show breakdown voltages greater than 95 percent of the ideal breakdown voltage with lower leakage currents than corresponding unimplanted devices. As an example, plane-junction moat-etch-terminated diodes with a normal breakdown voltage of 1050 V and a 0.5-mA leakage current become 1400 V (1450 ideal) devices with a 5-µA leakage current. Planar junctions, which broke down at 300 V, blocked as much as 1400 V if JTE terminated. Since planar junctions are of the greatest interest, we incorporated multiple field ring, field plate, and JTE terminations on a mask set and fabricated and tested thousands of devices. The results clearly showed that the ideal breakdown voltage can be achieved with less than 200 µm with JTE, where the same area would lead to 30 to 45 percent of the ideal with field rings and up to 40 to 50 percent of the ideal when used with field rings combined with field plates. Eight rings, even combined with a field plate, yielded less than 80 percent of the ideal breakdown voltage and required about 400 µm of device periphery.

Anomalous temperature dependence of threshold for thin quantum well AlGaAs diode lasers

Abstract: Thermally induced threshold wavelength shifts of 50 nm have been observed in short cavity length diode lasers fabricated from thin quantum well AlGaAs. Analysis suggests that the high‐energy radiation is generated by transitions between the n=2 level in the conduction band and the n=2 heavy hole level in the valence band. The threshold characteristic temperature (T0) of the laser material is found to be a strong function of cavity length.

New ultrafast switching mechanism in semiconductor heterostructures

Abstract: A new switching mechanism in a two‐terminal semiconductor heterolayer structure is proposed which capitalizes on nonlinear electron temperature effects in adjacent heterolayers. The estimated switching speed of an optimized heterostructure hot electron diode should be extremely fast, perhaps as fast as 200 fs. Data are presented on prototype devices which show the expected negative differential resistance and indicate that the basic physical model is correct.

Semiconductor heterojunction topics: Introduction and overview

Abstract: Semiconductor heterojunctions with ideal lattice matching, well-controlled in fabrication, yield devices that cannot be achieved in any other way. These devices include modulated-doped high-speed field-effect transistors, ultra-high-gain and high-speed bipolar transistors, efficient injection lasers and light-emitting diodes and sensitive photo-detecting structures. Atomic reconstructions take place at heterojunction interfaces and are process-fabrication-dependent and not adequately understood. The barrier discontinuities observed are therefore scattered in value and also somewhat dependent on the determination method. Many papers in this Special Issue contain review aspects of these matters. Others, however, are specific contributions on very particular heterojunction topics. Not all aspects of heterojunctions are dealt with by the papers that follow, and the present article is intended for newcomers to the field as a brief commentary on topics that are not adequately represented.

Observation of resonant tunneling in AlGaAs/GaAs triple barrier diodes

Abstract: Resonant tunneling and accompanying negative differential resistance are observed at 85 K in Al0.4Ga0.6As/GaAs triple barrier diodes, where two GaAs wells are separated by three AlGaAs barriers. Five resonance peaks, one small peak for one bias polarity, one medium and one large peak for each bias polarity, are observed. These are the resonance current peaks from the ground level of a populated well to the ground, the first excited or the second excited level of an adjoining unpopulated well. These are the direct electrical observations of the resonant tunneling between confined electron states in two potential wells of a semiconductor multiheterostructure.

Charge transfer device

Abstract: PURPOSE:To form a SAW-CTD having a wide dynamic range by shaping a channel-stop for preventing a removal from a transfer channel of charge carriers and a storage section for charge carriers into the transfer channel or in the vicinity of the transfer channel. CONSTITUTION:With a channel-stop 23, a P type semiconductor may be diffused to the periphery of an aimed transfer channel such as a section in the vicinity of the surface of a P-type semiconductor on the P-type semiconductor, and a conductor layer may be shaped onto an insulating layer while holding the insulating layer formed onto the P-type semiconductor and negative voltage may be applied. When the application of the voltage of a series of electrodes 24 is released gradually in the direction opposite to the direction 17 of the propagation of the waves 18 of potential and the formation of each potential well of storage sections 30 is removed in succession, charge carriers 25 being constrained to the storage sections 30 are constrained to the troughes of the waves 18 of potential, thus transferring the charge carriers 25. When the applica tion of the voltage is released at proper time intervals in succession, charge carriers 25 are transferred at time intervals corresponding to the positions of several storage section 30, and detected by a detecting diode 22.

Monolithic antenna with integral pin diode tuning

Abstract: Antennas chiefly intended for microwave and millimeter-wave use include geometric-shaped conductive patches on one broad surface of a planar semiconductor substrate. The other broad side of the substrate bears a conductive ground plane. Monolithic PIN diodes are formed by doping the substrate at various points between the conductive patch and the ground plane. Biasing arrangements affect the conduction of the PIN diodes thereby affecting or tuning the optimum operating frequency, the radiation pattern, and/or the impedance of the antenna. In a particularly advantageous configuration, the PIN diodes have lateral dimensions greater than or equal to one-tenth wavelength (λ/10) at the operating frequency. Distributed diodes have lower resistance and reactance than discrete or discrete monolithic diodes, thereby providing improved radiating characteristics, and have a relatively large power-handling capability which makes them useful for power transmission.

A symmetric submicron CMOS technology

Abstract: A CMOS process is described that is designed to optimize the transistor characteristics of the n-channel and p-channel devices simultaneously. This is achieved by making the n- and p-channel devices symmetric in channel doping, junction depths, sheet resistivities and threshold voltages. The resulting devices have CoSi 2 source/drains with sheet resistivities of 1.5-2 Ω/square, n+ and p+ polysilicon/TaSi 2 gate structures, Threshold voltages of 0.4 V and 1.5 µm separation between active to tub-edge regions. Diode characteristics of the CoSi 2 /n+ and CoSi 2 /P+ are determined to be as good as non-silicided silicon junctions. Maintaining the proper doping for the connected n+ and p+ polysilicon/silicide gates is demonstrated. Ring oscillator delays of 110 ps at 3.5 V are observed for devices with 0.5 µm channel lengths. The ring oscillator circuits are still operational at power supply voltages of 1.0 V due to the low threshold voltage of the transistors.

Precise Control of Resonant Tunneling Current in AlAs/GaAs/AlAs Double Barrier Diodes with Atomically-Controlled Barrier Widths

Abstract: The resonant tunneling current is studied in AlAs/GaAs/AlAs double barrier heterostructures in which the barrier widths LB are precisely controlled to be exactly 5, 8 and 11 atomic monolayers. It is demonstrated for the first time that the density of resonant current in these diodes can be controlled from 5×102 Acm-2 to 1.2×104 Acm-2 by the choice of LB, in accordance with the theoretical calculations. Furthermore, I–V characteristics of these devices are shown to be excellent with peak-to-valley ratios of 2.3 at room temperature and 10 at 80 K, the highest values ever reported.

Semiconductor analysis using organic-on-inorganic contact barriers. I. Theory of the effects of surface states on diode potential and ac admittance

Abstract: A new method for measuring the density of states at semiconductor surfaces using organic‐on‐inorganic (OI) semiconductor contact barriers is suggested. This work is an extension of previous models of OI diode behavior which includes the ac admittance characteristics, and which considers the range of validity of approximations to OI diode capacitance used in previous experiments. The theory describes the potential distribution across the device. We consider the case of ideal OI diodes, as well as diodes with significant densities of states at the inorganic semiconductor surface. This analysis leads to a technique whereby the low‐frequency conductance and capacitance characteristics can be used to obtain information about the magnitude and the energy distribution of surface states in the inorganic semiconductor bandgap. Also, the carrier concentration profiles of the substrate can be conveniently obtained. Due to the noninvasive nature of the organic/inorganic contact, information about the density of states at relatively undisturbed semiconductor surfaces obtained via this technique may prove useful in determining the processes involved in Schottky barrier formation and metal‐insulator‐semiconductor diode surface properties. This theory has been applied to the investigation of surfaces of III‐V alloy semiconductor‐based OI diodes, and the experimental results will be presented in a subsequent paper. In addition, an expression for the OI diode n value obtained from the forward current‐voltage characteristics is derived. It is found that the n value depends on surface states which are in equilibrium with the organic as well as the inorganic materials. Estimates of the surface state densities obtained from previously reported n values are consistent with expectations for the semiconductors under test.

Ultra-high-speed modulation of 1.3-&#181;m InGaAsP diode lasers

Abstract: The differential gain of 1.3 μm InGaAsP lasers is found to be a strong function of the active layer doping level. Using devices with doping enhanced differential gain and short cavity lengths, a modulation bandwidth of 15 GHz is achieved. The parasitic shunt capacitance which often severely limits the modulation bandwidth of diode lasers is greatly reduced by using a 0.4 μm thick oxide isolation layer and a device structure which minimizes parasitic capacitances. It is found that nonlinear gain saturation predominantly determines the damping factor of these devices, and thus greatly influences their modulation characteristics. The contribution of nonlinear gain to the FM modulation index and relaxation oscillation damping factor is calculated and measured. The nonlinear gain contribution to the damping factor obtained from the measured FM modulation index is used to predict the optical intensity modulation response. Excellent agreement between prediction and observation is obtained. These data directly show that the damping factor of multilongitudinal-mode lasers is smaller than that of single-mode lasers, suggesting that wider modulation bandwidths can be achieved with multimode devices than with single-mode devices.

Dynamics of a virtual cathode oscillator driven by a pinched diode

Abstract: A new method is demonstrated for extracting radiation from a virtual cathode oscillator in transverse electric (TE) waveguide modes. The dominant radiation mechanism occurs in the region of the virtual cathode, and is not due to reflexing of electrons. Microwave radiation occurs simultaneously or just after beam pinching in the diode. Electrostatic signals show simultaneous occurrence of the virtual cathode and microwave radiation. At the same time, the electron population divides into a beam population and a reflexing electron population. Inhibition of pinching by an axial guide field suppresses microwave radiation.

Oxygen measurement using visible radiation

Abstract: Apparatus for measuring the absorption of a gaseous sample and particularly suitable for measuring the concentration of gaseous oxygen makes use of a diode laser whose emission wavelength is adjacent to but spaced from the wavelength of a distinct absorption line. The diode drive current is altered to cause the junction temperature of the laser to change, thereby changing the wavelength of the emitted radiation and in effect scanning it through a range of wavelengths that includes the absorption line. The absorption is determined by a ratio technique and therefore is independent of changes in the laser output power level and drifts and changes in other parts of the optical system.

Anomalous length dependence of threshold for thin quantum well AlGaAs diode lasers

Abstract: The threshold current in conventional semiconductor diode lasers decreases linearly with decreasing cavity length. We have found that for AlGaAs diode lasers fabricated from very thin active layer material, the threshold current can be essentially constant over a wide range of cavity lengths. At short cavity lengths, threshold increases dramatically. This anaomalous behaviour is attributed to physical mechanisms which become important when active layer threshold gain requirements become unusually high.

Observations of subpicosecond dynamics in GaAlAs laser diodes

Abstract: We present results of pump‐probe experiments on GaAlAs laser diodes indicating a 0.9‐ps relaxation time associated with the device transmission. Subpicosecond, tunable near infrared pulses obtained by fiber compression were used to carry out the experiments. The data strongly support a model in which a nonequilibrium carrier temperature in the active layer is responsible for the observed signal.

Gate‐controlled Hg1−xCdxTe photodiodes passivated with native sulfides

Abstract: The properties of ion‐implanted junctions in Hg1−xCdxTe with x=0.22, passivated by a novel native sulfide technique, are described. The junctions are typically operated at 77 K, with 50% responsivity at a wavelength of 10.5 μm. To study the effects of the passivated surface on the diode properties, special gate‐controlled diodes were processed, including both nickel and titanium gate metals. In addition, a novel enhancement mode metal–insulator–semiconductor field‐effect transistor (MISFET) is presented. The measured dc properties and noise current spectral densities of various diodes as a function of reverse bias and gate control voltage show that close to background limited devices may be realized with the above surface passivation. In particular, such diodes exhibit good 1/f noise performance at low frequency, with reverse bias of close to 200 mV, without requiring a special gate electrode.

Schottky-barrier height determination in the presence of interfacial disorder

Abstract: By including the effects of electron-hole recombination and electron trapping in the analysis of the transport properties of Schottky diodes it is possible to obtain a more accurate estimate of the Schottky-barrier height. The magnitude of the barrier height obtained from an analysis of the forward I-V characteristics of CdTe Schottky diodes is in better agreement with that obtained from C-V measurements than that obtained by using the conventional procedure of introducing an ideality factor into the 'ideal diode' equation.

Study of ballistic transport in Si‐CoSi2‐Si metal base transistors

Abstract: The hot‐electron transfer ratio from the Schottky emitter diode to the Schottky collector diode through the thin base layer of Si‐CoSi2‐Si metal base transistors has been measured in devices for which the pinhole contribution to the current gain is shown by transconductance measurements to be negligible. The common‐base current gain α of the transistors, measured as a function of temperature and base thickness, exhibits an exponential dependence on CoSi2 film thickness, from which a ballistic mean free path is deduced. This value is in good agreement with the mean free path deduced from conductivity data, both at 77 and 300 K. The behavior of the pre‐exponential coefficient, i.e., the gain extrapolated to zero base thickness, is not completely understood and shows evidence for hot‐electron and space‐charge effects in the epitaxial overgrown Si material of the emitter.