Showing papers on "Diode published in 1982"

Defect production and lifetime control in electron and γ‐irradiated silicon

Abstract: A study of the effect of 1‐ and 12‐MeV electron and Co60 γ irradiation has been made on power p‐i‐ n diodes and Schottky barrier diodes fabricated on the same starting material. A comparison of the results from these two types of structures illustrated the influence of device processing on the type of defects formed by subsequent irradiation. Detailed electrical characterization of the defects demonstrated good consistency between certain elements of the structural nature of the defect, inferred from these measurements, and those already obtained from electron spin resonance (ESR) measurements. Lifetime measurements on the p‐i‐n diodes indicated that both the A center and the divacancy were active recombination centers. Finally, data are presented on defect and lifetime annealing.

Modeling and measurement of minority-carrier lifetime versus doping in diffused layers of n + -p silicon diodes

Abstract: The results of minority-carrier lifetime measurements in heavily phosphorus-doped n+diffused layers of p-n junction diodes using a spectral response technique are reported in this paper. Exact modeling of current-flow equations, modified to include bandgap reduction due to high carrier concentration and Auger recombination, is used to compute the dependence of diffused-layer photocurrent J pth on the incident light energy and intensity. The photocurrent in the diffused layer is also obtained by subtracting the theoretical value of the space charge and uniformly doped p-region component from the experimentally measured photocurrent of the diode at each wavelength. Note that all calculated values based on light intensity include computed transmittance/reflectance through the oxide layer at each wavelength. The comparison of the values of J pth with J pexp , using nonlinear least square techniques, then directly gives the lifetime profile in the diffused layer. A simple expression is given for lifetime as a function of doping which may be used in modeling and prediction of device performance. Using this experimental technique it was found that the lifetime in the diffused layer is an order of magnitude less than that corresponding to uniformly doped bulk-silicon values and is very much process dependent; its value being 3.72 × 10-11s for surface concentration of 3.0 × 1020cm-3and increases to 2.9 × 10-8s at doping concentration of 1.0 × 1017cm-3.

Method and device for analyzing a very high frequency radiation beam of electromagnetic waves

Abstract: The invention refers to the analysis of a very high frequency radiation beam of electromagnetic waves. According to the invention, a network of conductor wires is placed in the path of a beam to be analyzed, the wires being interrupted at intervals by switches. One controls the conducting state of a diode and one blocks the others and one makes the position of the diode vary electronically and sequentially in the conducting state. The return signal received on a sensor R is used by detecting the significant characteristics of that return according to the position of the diodes in the conducting state.

Bistability and pulsations in semiconductor lasers with inhomogeneous current injection

Abstract: Bistability and pulsation at microwave frequencies are observed in CW GaAs semiconductor lasers with inhomogeneous current injection. Inhomogeneous current injection is achieved with a segmented contact structure. Crucial to the understanding of the characteristics of this device is the discovery of a negative differential electrical resistance across the contacts of the absorbing section. Depending on the electrical bias condition, this negative differential resistance leads to bistability or light-jumps and self pulsations. A simple model based on conventional rate equations with a linear gain dependence on carrier density explains the observed behavior and suggests a new mechanism in inhomogeneously pumped diode lasers for light-jumps and pulsations which does not depend on the condition for the usually proposed repetitively Q -switching. Investigation of the switching dynamics of this bistable optoelectronic device reveals a delay time which is critically dependent on the trigger pulse amplitude and typically on the order of a few nanoseconds with power-delay products of 100 pJ. The observed critical slowing down and its origin is discussed. We also report on the characteristic of this laser coupled to an external optical cavity and we demonstrate successfully that this bistable laser can be used as a self coupled stylus for optical disk readout with an excellent signal to noise ratio.

Grain boundary states and the characteristics of lateral polysilicon diodes

Abstract: In lateral n+p−p+ diodes made in LPCVD polycrystalline silicon films, the energy distribution of the traps at the grain boundaries is found to be U shaped. They have a density of about 1012 cm−2 and a capture cross section of about 10−16 cm2. The forward current of the diodes is ascribed to recombination, the reverse current to field-enhanced generation via these traps.

Distributed series resistance effects in solar cells

Abstract: A mathematical treatment is presented of the effects of one-dimensional distributed series resistance in solar cells. A general perturbation theory is developed, including consistently the induced spatial variation of diode current density and leading to a first-order equivalent lumped resistance of one third the total sheet resistance. For the case of diode characteristics of exponential type and distributed resistance of arbitrary size, unified numerical results are presented for both illuminated and dark characteristics. At high forward dark currents, the distributed series resistance is shown to cause an effective doubling of the "diode quality factor."

Active-Quenching and Gating Circuits for Single-Photon Avalanche Diodes (SPADs)

Abstract: Single-photon detection by avalanche photodiodes with uniform breakdown over the junction area (single--photon avalanche diodes SPADs) is well known. The active quenching method, introduced by the authors, has been shown to avoid drawbacks of passive-quenching circuits and provide accurate operation of the devices. New active-quenching circuits are here presented. Dead times below 20 ns are obtained. A fast gating control acting directly on the photodetector has been developed, in view of timing studies with closely-spaced ultrashort light pulses.

Silicon carbide blue light emitting diodes with improved external quantum efficiency

Abstract: The most relevant features in the fabrication and room temperature operation of blue light emitting 6H‐SiC:Al,N diodes are reported. Epilayers are grown either on opaque Acheson substrates or on semi‐ to fully transparent substrate platelets obtained from larger ingots grown in our laboratory. The p‐n junction is obtained by overcompensating Al acceptors with N donors. Electroluminescent light, which is mainly due to N‐donor‐Al‐acceptor pair recombination is generated in the n region of the diode. The emission spectrum is saturated to about 90% at normal driving conditions, the hue of the diodes being slightly dependent on the current density. Optimization of diode preparation and design, especially the use of transparent substrates, yields external quantum efficiencies of 1.1×10−4 for unencapsulated samples, nearly triplicating the best quantum efficiency values for SiC:Al,N diodes reported so far.

Longitudinal mode spectra of diode lasers

Abstract: A theory is presented which explains the longitudinal mode spectra of diode lasers. The theory is based on spontaneous emission coupling into the longitudinal modes and the excellent agreement with experimental data for both gain guided and real refractive index waveguide diode lasers is obtained because of the more accurate and detailed modeling of the spontaneous emission coupling and the laser itself.

Measurements of mode partition noise of laser diodes

Abstract: Mode partition noise may become the dominant performance limitation for single-mode fiber systems. We define the mode partition coefficient k for laser diodes which can be used as a universal index, like threshold current and spectral width, to characterize laser diodes. The k value varies between 1 and 0, and for larger k , the mode partition noise will be higher. We also demonstrate two simple techniques for measuring k : the low-pass filter method and the sampling method. We discuss the k values measured under different operating conditions (pulse width, dc bias) for several types of laser diodes, k values are around 0.4-0.6 with short pulse width (1.5-5ns), and decreases to 0.14 pulse width of 50 ns. The largest k values were obtained for a laser exhibiting strong relaxation oscillation. For that laser, k did not depend on the pulse width. The k value is an important factor for system and fiber design as well as laser diode design.

Photoluminescence dead layer in p‐type InP

Abstract: Photoluminescence intensity of p‐type InP Schottky diodes was measured as a function of excitation wavelength for several values of applied bias. The intensity increases with penetration depth of the excitation radiation and is quantitatively consistent with a nonradiating surface dead layer. The dead‐layer thickness is somewhat less than the diode depletion width, but has the same functional dependence on applied bias.

Generation of subpicosecond coherent optical pulses by passive mode locking of an AlGaAs diode laser

Abstract: Subpicosecond coherent optical pulses as short as 0.58 ps were generated for the first time by passive mode locking of an AlGaAs double heterostructure diode laser. It was realized by a simple configuration made of a conventional AlGaAs diode laser without antireflection coatings on both facets, which was aged and exhibiting self‐pulsation, placed in an external cavity. When the external cavity length was shorter than about 60 mm, almost complete mode locking was observed over the oscillation spectrum of 3.5 nm in width. Based on the second‐harmonic generation autocorrelation measurement, ultrashort coherent optical pulses from 0.58 to 1.2 ps in duration were demonstrated by increasing the external cavity length together with the proper control of the optical feedback effect and the pumping dc current.

Interfacial layer-thermionic-diffusion theory for the Schottky barrier diode

Abstract: A synthesis theory for majority‐carrier transports across the Schottky barrier diode has been developed by including the transport mechanisms across the interfacial layer and the effects of both thermionic emission and diffusion in the space‐charge region of the semiconductor. This theory incorporates the thermionic emission theory, diffusion theory, thermionic‐diffusion theory, and interfacial layer theory into a single theory: the interfacial layer‐thermionic‐diffusion theory. The major improvement of the proposed theory over the thermionic‐diffusion theory is that the applied voltage drop and transmission coefficient across the interfacial layer are included, thus enabling us to interpret the characteristics observed from the Schottky barrier diodes fabricated with different metals and substrate materials by means of different fabrication conditions. Moreover, based on the developed interfacial layer‐thermionic‐diffusion theory, the characteristic parameters of the Schottky barrier diode, such as the barrier height, ideality factor, and the reverse current, have also been derived and discussed.

On the current‐voltage characteristics of amorphous hydrogenated silicon Schottky diodes

Abstract: First principle calculations of amorphous hydrogenated silicon Schottky barrier and p‐i‐n diodes’ current‐voltage characteristics have revealed an interesting relation between the observed quality factor and the composition of the diode current. The diode current consists of two components: (1) The drift/diffusion current, JD, which is virtually independent of carrier recombination mechanism, and (2) the recombination current JR. Each component has a characteristic value of the quality factor, β (inverse slope of semilog J‐V plot): β<1.1 for JD and β⩾1.6 for JR. In addition, the relative magnitudes of the two components vary with the device thickness, the density of localized states, and the surface barrier potential. The difference in the quality factors observed in Schottky barriers and in p‐i‐n diodes can be interpreted as an indication of change in the dominant component from JD to JR, due to a larger surface potential in the latter device.

Solid state image pickup device

Abstract: PURPOSE:To inhibit dark currents generated at a light receiving diode section to low value by forming the first storage gate determining potential and the second storage gate substantially storing charges while being adjoined to the light receiving diode section shaped onto a substrate. CONSTITUTION:An N type diffusion layer 23 is formed to the P type substrate 21, and the light receiving diode section is shaped. The second storage gate 27 is formed to a section corresponding between ion injection layers 24, 25 and the first storage gate 28, a transfer gate 29 and a gate 30 of a CCD register in a shape that adjoins to the gate 29 to a sections corresponding to the injection layers on the injection layers 24, 25 and a gate oxide film molded onto the substrate 21. Hot carriers are generated by beams projected from a window 33 and caught by the diode section, and move to the stable second storge gate 27 and are stored. Accordingly, dark currents are decreased, the potential of the light receiving diode is kept constant, and photoelectric conversion is conducted.

Gain and bandwidth of fast near-infrared photodetectors: A comparison of diodes, phototransistors, and photoconductive devices

Abstract: Different materials and different types of detectors are used for optical data communication in the wavelength range of \lambda \sim 0.8 µm \lambda \sim 1.7 µm. In this paper the behavior of p-n diodes, Mn and Mp Schottky diodes is evaluated as well as that of bipolar transistors, n-p-n and p-n-p, and of photoconductive detectors using n-type or p-type material. The different behavior of lateral and coaxial versions is shown taking into account contact and surface recombination. The gain, the bandwidth, the gain bandwidth product, and the rise time of all these types of fast detectors are given in terms of material and technological data, including the discussion of the different rise and fall times of some detector versions. Finally, a theoretical comparison is made between the detectors showing their different behavior and ultimate performance limit. For practical GaAs planar devices as a photoconductive detector, a p-n diode, a heterojunction n-p-n and a lateral n-p-n transistor, a Mn Schottky diode, and a totally depleted MnM structure (symmetrical Mott barrier) experimental data are given. They verify the theoretical prediction that with all types of detectors rise times of <100 ps can be achieved.

Spectrophotometry and Spectrofluorometry with the Self-Scanned Photodiode Array:

Abstract: A state-of-the-art self-scanned photodiode array, utilized as a spectrometric multichannel detector, was studied for its applicability to molecular absorption and molecular fluorescence spectrometry. Molecular absorption spectrophotometry requires detectors with high UV to near IR response, high dynamic range, linear response, low noise, and temporal as well as thermal stability. Molecular fluorescence spectrometry requires, in addition, sensitivity to low-light level signals. These requirements were satisfied by the systems under study. Other parameters that govern the overall performance of diode array-based spectrophotometers and spectrofluorometers include: photometric range, stray energy radiation and its effect on photometric accuracy, photometric precision, spectral resolution sensitivity, and signal-to-noise considerations. Various readout methods for the array detectors were examined including: real time, in-memory signal integration, on-target signal integration, variable integration time (VIT), diode grouping, and diode fast access (a pseudorandom access readout). Performance demonstrations of these multichannel spectrometers were made with a few typical chemical systems. The spectrophotometric performance of the diode array system was excellent, practically equal to that of conventional single-channel systems. Exceptions were higher amenability to the adverse effects of stray radiation energy and a dependency of the geometric (wavelength) accuracy on spatial fluctuations (wander) in the light source. Potential long-term UV degradation of diode arrays may present an inherent problem, but was not discussed here because data accumulated up-to-date was considered inconsequential. As a spectrofluorometer multichannel detector, the diode array showed an "unexpected" signal-to-noise (detectability) performance, closely matching that of conventional high gain detectors. However, this performance was achieved only if sufficiently long signal integration times (20 to 160 s) were feasible. Overall performance of the diode array has demonstrated that theoretical multiplex advantages are achievable, resulting in either a considerable improvement in signal-to-noise or a corresponding shortening in observation time.

Carrier lifetime measurement for determination of recombination rates and doping levels of III-V semiconductor light sources

Abstract: A novel method is described for measuring the carrier lifetimes in double heterostructure light‐emitting diodes (LED’s) and lasers. The improved resolution of the technique permits the first reported measurement of the carrier dependence of the radiative recombination coefficient. The technique also provides a reliable measurement of the active region doping level which is in very good agreement with the values calculated from the composition of the growth solutions.

AC Transistor switch with overcurrent protection

Abstract: An AC transistor switch is provided with simple, accurate and fast overcurrent protection circuitry. A pair of transistors are connected in anti-series across an AC load line, and each transistor has an anti-parallel diode therearound conducting current in the alternate half cycles. Comparator means senses current flow through the diodes and is responsive to given threshold overload current to turn off the transistors. Voltage sensing means is referenced to a common point between the series connected transistors and senses the voltage at each main terminal relative to the common point to thus sense the voltage drop from the common point across each diode to its respective main terminal for sensing current flow through the respective diode. The current representative voltage is sensed through respective dedicated third and fourth diodes connected to the main terminals and having a common anode connection to the voltage sensing means such that the latter senses the more negative of the main terminals regardless of the relative potential therebetween.

A method for determining energy gap narrowing in highly doped semiconductors

Abstract: A general experimental method for the determination of the phenomenological energy gap narrowing \DeltaE_{G} in regions of semiconductor devices that have high concentrations of donor or acceptor impurity atoms is presented. The theoretical grounds for the method are discussed in detail, including the strong influence of Fermi-Dirac statistics on minority-carrier recombination in heavily doped regions. The method requires measurements only of the temperature dependence of de current; therefore it is very accurate. The values of \DeltaE_{G} deduced from the method are insensitive to the mechanisms controlling recombination and to the value of minority-carrier mobility in the heavily doped region; they are also independent of the value of n i the intrinsic carrier density, at a specific temperature. The values for the Si:As emitters of transistors and diodes were measured in the majority-carrier concentration range from 4 × 1018cm-3to 2 × 1020cm-3.

Electrical and optical characteristics of a schottky barrier on a cleaved surface of the layered semiconductor InSe

Abstract: Forward current-voltage characteristics at various temperatures and the frequency depencence of barrier capacitance in Au/InSe Schottky barrier diodes are investigated in detail. The origin of an excess temperature T0 and the effect of electron traps on the barrier capacitance are discussed. Strom-Spannungscharakteristiken bei verschiedenen Temperaturen und die Frequenzabhangigkeit der Sperrschicht-Kapazitat von Au/InSe-Schottky-Dioden werden ausfuhrlich untersucht. Die Ursache der Rest-Temperatur T0 und der Einflus der Elektronenhaftstellen auf die Sperrschicht-Kapazitat werden diskutiert.

Prevention of latch-up in CMOS integrated circuits using Schottky diodes

Abstract: A complementary metal oxide semiconductor (CMOS) circuit is described incorporating Schottky barrier diodes in parallel with the source or drain of either the P or N channel transistors to reduce the minority current injected into the body at times the source or drain of either the N or P channel transistors are forward biased. The Schottky diode may be fabricated by making enlarged openings exposing both the body (substrate) and drain or source region and by using a metallization which may form an ohmic contact with the drain or source region and at the same time for a Schottky diode with the substrate. By incorporating Schottky barrier diodes parallel to the drain or source the P and N-type transistors are not current limited by the barrier height of only a Schottky diode acting as the source and at the same time minority current is not injected into the substrate or body at times the drain or source is forward biased. An input and output protection network is also described incorporating Schottky diodes.

Laser annealing study of the grain size effect in polycrystalline silicon Schottky diodes

Abstract: Laser annealing is used to controllably vary the grain size of polycrystalline silicon films. The properties of Schottky diodes formed in such layers are studied experimentally by I‐V and C‐V measurements and interpreted in the framework of the grain boundary trapping model for polycrystalline silicon. For large grained material (grain size ≊10 μm) nearly ideal Schottky diode characteristics with a diode factor n close to unity are found. As deposited, fine grained material is fully depleted at the doping levels employed and yields a p‐i‐n diode behavior characterized by n=2. Observation of this regime without series resistance limitations is possible by using a buried n+ layer as the back contact of the diodes. Reverse currents of the diodes are inversely proportional to the grain size, as expected for generation at grain boundary traps.

Pin diode switched impedance matching network having diode driver circuits transparent to RF potential

Abstract: A coupler network with pin diode switches receives biasing and control information through a biasing network that is essentially transparent to the RF operation of the coupler network.

Manufacture of semiconductor device

Abstract: PURPOSE:To improve light emitting efficiency and the characteristics of modulation by a method wherein a PN junction of a light emitting diode is prepared through liquid-phase epitaxial growth, and a semi-insulating semiconductor layer and an active layer of a FET are formed through a molecular beam epitaxial method in the semiconductor device controlling the light emitting output of the diode by the input signals of the FET connected in series. CONSTITUTION:The light emitting diode is manufactured in such a manner than an N type Ga0.8Al0.2As layer 12 and a P type Ga0.9Al0.1 As layer 13 are laminated and deposited on an N type GaAs substrate 11 through the slide board type liquid-phase epitaxial growth method and the PN junction is formed between the layers 12 and 13. A P type Ga0.7Al0.3As layer 14 is further grown on the layer 13 in a liquid phase in order to decrease contact resistance. The element is admitted into another device and grown through the molecular beam epitaxial growth method, but an N type or undoped GaAs layer 15 is shaped previously in order to prevent contact with air and the discontinuance of the layer 14 at that time. A GaAs layer 16 is grown through the molecular epitaxial growth method and used as the semi-insulating semiconductor layer, and an N type CaAs layer 17 functioning as the active layer of the FET is grown on the layer through the same method.

Multi-phase transistor/diode bridge circuit

Abstract: A three-phase bridge circuit includes two sets of transistor/diode assemblies in which the diode of each assembly is connected in reverse current mode across the main current path of its transistor. Each diode of one set has its cathode connected to a positive d.c. input bus bar and its anode to a respective a.c. output bus bar. Each diode of the second set has its cathode connected to a negative d.c. input bus bar and a respective a.c. output bus bar. An input terminal has a plurality of electrical contacts, each connected to the control electrode of a respective transistor in the transistor/diode assemblies. A heat sink has its electrically insulating layer on one major surface thereof and in thermal contact therewith. Each transistor is in thermal contact with the heat sink by way of a bus bar part, and each of the bus bar parts is secured to the insulating layer so as to be in thermal contact with the heat sink.

PdInP Schottky diode hydrogen sensors

Abstract: PdInP Schottky diodes are shown to be very sensitive and reproducible detectors of hydrogen. Absorption or desorption of hydrogen by Pd causes large changes in the diode C – V or I–V characteristics. Fourfold increase in capacitance is observed on exposing the device to forming gas. We present data on sensitivity of these devices, their transient response and detection mechanism.