Showing papers on "Diode published in 1976"

Theory of life time measurements with the scanning electron microscope: steady state

Abstract: A theoretical steady state analysis is given of the scanning electron microscope method of measuring bulk life time in diodes, where the plane of the junction is perpendicular to the surface. The current in the junction is obtained as a function of the beam power, the beam penetration into the semiconductor, the value of the surface recombination velocity, and the distance of the beam to the junction. Particular attention is paid to the injection level, and sufficient conditions are formulated for low and high injection, in terms of the beam current and voltage. A new method for measuring large surface recombination velocities is suggested.

Schottky‐barrier characteristics of metal–amorphous‐silicon diodes

Abstract: Metal–amorphous‐silicon Schottky barriers, similar to those used in thin‐film amorphous‐silicon solar cells, exhibit nearly ideal diode behavior in the dark. The current‐voltage characteristics have been studied in the range from 270 to 370 °K and are found to be in agreement with the diffusion theory of metal‐semiconductor rectification. Barrier heights, which were measured by two different methods, depend on the metal work function, and barriers as high as ∼1.1 eV are obtained with Pt films.

The effects of sputtering damage on the characteristics of molybdenum-silicon Schottky barrier diodes

Abstract: The properties of d.c. sputtered molybdenum-silicon Schottky diodes are described. Although it is possible to produce near ideal characteristics when a low sputtering voltage is used for a short time, increased voltage and time lead to significant deviation from the ideal. A model is proposed which is capable of explaining most features of the observed C-V and I-V characteristics. This model assumes that sputtering damage causes donor-like traps to be created close to the semiconductor surface. It is found that an exponential distribution of traps with characteristic length in the range 10–100 A and an energy level of 0·43 eV below the conduction band is sufficient to account for the observed characteristics. The modification to the I–V characteristics is due to tunnelling through the top of the Schottky barrier where it is narrowed by the presence of the excess trapped charge.

Quantum efficiency of the internal photoelectric effect in silicon and germanium

Abstract: The quantum efficiency of silicon and germanium has been measured for photon energies up to 6 eV for Si and 5.3 eV for Ge. Diodes have been constructed with unity collection coefficient in this spectral range. The observed quantum efficieny of silicon in the ultraviolet is much smaller than hitherto believed, i.e., a value of 1.50 is found at 6 eV. The results for Ge accidentally agree with Vavilov and Britsyn’s measurements. An analysis of sources of error in quantum‐efficiency measurements is given.

Solar magnetograph employing integrated diode arrays.

Abstract: A solar magnetograph employing as detectors a pair of self-scanning 512-element integrated diode arrays is described. Coupled to a 1.5-m telescope, photospheric flux as small as 5(106) maxwells is detected, corresponding in intensity to ΔI/I = 3(10−4) at λ0.8688 μm. Measured photometric properties of the diode array are given, including MTF as a function of wavelength, dark current as a function of temperature, completeness of readout, optical and electronic fixed-pattern noise. An integrating preamplifier is presented that achieves a measured noise, when connected to the array, equivalent to 950 electrons at the input for a bandwidth of 3(105) Hz. These data provide a basis for an evaluation of the detector performance at low light levels beyond the needs of the magnetograph. Operated at near liquid nitrogen temperature, the noise and cooling characteristics indicate the detector has promise as a low light level sensor.

Electroluminescence in amorphous silicon

Abstract: Electroluminescence has been obtained in forward‐biased p‐i‐n diodes, and also in Schottky barrier diodes fabricated from discharge‐produced amorphous Si. The emission at 78 °K in both electroluminescence and photoluminescence peaks at 1.28±0.08 eV in a 0.2‐eV broad band with an external quantum efficiency of ∼10−3.

Electrical and Optical Properties of GaSe-SnO 2 Heterojunctions

Abstract: The capacitance-voltage (C-V) and forward biased current-voltage (I-V) characteristics, electroluminescence (E.L) and photovoltaic effect of GaSe–SnO2 heterojunction diodes are measured. SnO2 layer is deposited on the c-plane of GaSe by using the spray method. The C-V and I-V characteristics of these diodes reveal the existence of a high resistivity layer, probably due to the diffusion of Sn into GaSe. The width of this layer is about 2.6 µm. And the current transport mechanism at low voltage is space-charge-limited. The trap density and the energy level of the trap from the valence band estimated by Lampert theory are about 5×1013~1×1014 cm-3 and 0.4~0.6 eV, respectively. The electroluminescence spectra at 275 K show one emission band due to free exciton recombination.

Derivative measurements of the current-voltage characteristics of double-heterostructure injection lasers

Abstract: Measurements of the electrical characteristics of double-heterostructure (DH) stripe-geometry AlGaAs junction lasers are reported. We show that the electrical characteristics of these lasers are adequately represented by a resistor in series with a p-n junction characterized by a classical diode equation, I = I_{s} [\exp (q V_{j}/\etakT) - 1] . Devices have been measured with almost ideal junction characteristics with both the saturation current, I s , and the exponential parameter, η, constant, while in other diodes both η and I s exhibit a strong current dependence. Measurement of the first derivative dV/dI and the product IdV/dI is shown to be an especially useful technique for electrical characterization, yielding accurate and direct determination of the series resistance, the exponential junction parameter, and the laser threshold current. The observation of lasing threshold from an electrical measurement, instead of from the more usual optical measurement, is discussed in terms of the saturation behavior of the junction voltage at and above threshold.

Efficient lattice‐matched double‐heterostructure LED’s at 1.1 μm from GaxIn1−xAsyP1−y

Abstract: The growth and operation of lattice‐matched double‐heterostructure InP/Ga0.17In0.83As0.34P0.66/InP light‐emitting diodes is reported. These diodes have an emission wavelength of 1.1 μm and quantum efficiencies of 4%.

Silicide formation in Ni-Si Schottky barrier diodes

Abstract: Rutherford backscattering of energetic 4He+ ions has been used to study the composition and depth profile of silicide layers formed when thin nickel films evaporated on (111) and (100) silicon surfaces are heated in a nitrogen-hydrogen ambient. In the temperature range 297 to 430 degrees C two phases are seen to form sequentially. The growth of the first phase, Ni2Si, is parabolic with time, whilst the second, NiSi, grows linearly with time. The simultaneous presence of both diffusion and reaction-rate-limiting mechanisms is implied by the parabolic and linear growth laws. An investigation of the electrical characteristics of diodes which were metallized and heat-treated simultaneously shows little change in the barrier height.

Linear signal isolator and calibration circuit for electronic current transformer

Abstract: An optical data transmission system for use with current sensors on ac high voltage transmission lines comprises a light-emitting diode transmitter at line potential and a silicon photodiode receiver at ground potential. Signals are conducted from the transmitter to receiver along a fiber optic light pipe. A silicon photodiode in a feedback configuration produces a linear ac output light from the light-emitting diode in response to line current. A dc reference signal is superimposed on the ac current data signal to provide system gain calibration. The dc signal is utilized, in a feedback loop, to control the gain of an ac signal amplifier in the receiver and to thus stabilize system calibration.

Optimization of the Efficiency and Other Properties of the Rectenna Element

Abstract: The rectenna which captures and rectifies the microwave power at the receiving end of a free space microwave power transmission system is comprised of many elements consisting of halfwave dipoles with microwave filter and rectification circuits attached. This element has been independently optimized for efficiency and analyzed for losses. The paper describes the device, the special test equipment used, the results of the mathematical modelling and computer simulation, special low loss Schottky barrier diodes that have been constructed to improve the efficiency, and life tests that have been made on these devices. An efficiency, defined as the ratio of DC power output to incident microwave power, of over 90% has been achieved.

n-GaAs Schottky diodes metallized with Ti and Pt/Ti

Abstract: The electrical characteristics and interdiffusion in n -GaAs Schottky diodes containing Ti and Pt/Ti have been studied using I-V, C-V, X-ray diffraction and Rutherford backscattering measurements. Thermal aging of the diodes was carried out in vacuo at 350 and 500°C. The Ti/ n -GaAs diodes show near-ideal forward I-V characteristics with the ideality parameter n ⋍ 1·03 and the barrier height φ B ∼ 0·84 V . C-V data yield the same φ B . No interdiffusion was observed at 350°C. At 500°C, TiAs forms but the φ B remains unchanged. Pt/Ti/ n -GaAs diodes behave “Pt-like” upon aging at 500°C with φ B ∼ 0·9 V and n ∼ 1·1. The TiAs formed at 500°C is ineffective in preventing a subsequent Pt/GaAs interaction which leads to a layered arrangement of reaction products consisting of Pt 3 Ga/TiAs/PtAs 2 / n -GaAs.

C.W. oscillation with p+-p-n+ silicon IMPATT diodes in 200 GHz and 300 GHz bands

Abstract: Submillimetre-wave silicon single-drift-region IMPATT diodes with a p+?p?n+ structure have been fabricated by ion implantation. C.W. output powers of 7.5 mW at 285 GHz and 78 mW at 185 GHz were obtained. The maximum c.w. oscillation frequency observed was 394 GHz.

Bipolar read-only-memory unit having self-isolating bit-lines

Abstract: A semiconductor read-only-memory (ROM) unit fabricated in large-scale-integrated form utilizing the formation of self-isolating bit-line surface regions of one conductivity type directly in a bulk region of the opposite conductivity type. Channel-stop regions of the same conductivity type as the bulk region are formed in the spaces between bit-line regions. Metallic word-lines overlying and orthogonal to the bit-line regions are formed, separated from the bit-line regions by an insulating layer. The memory cell comprises a single Schottky diode. Such a diode is made or not at each word-line/bit-line crossover location depending respectively on whether or not an aperture is formed in the insulating layer during fabrication to permit the word-line to contact a lightly doped portion of the bit-line. ROM units formed by this method are characterized by small area, high speed, low power dissipation and low cost.

Barrier height enhancement in p-silicon MIS solar cells

Abstract: Calculations are presented which indicate that the barrier height of metal-thin insulator-p-silicon diodes can be greatly enhanced by the presence of positive charge in the interfacial layer. Application of the model to recent MIS silicon solar cell data suggests that oxide charge densities of 3-4 × 1012charges.cm-2could be responsible for the high performance of the reported cells.

Protection circuitry for insulated-gate field-effect transistor (IGFET) circuits

Abstract: The gate insulator of an IGFET, whose gate is connected to the input terminal of a circuit, is protected by limiting the potential difference between any two circuit terminals. Each input and output terminal of the circuit is connected via protective diodes to the power supply lines of the circuit and a high conductivity, low reverse dynamic impedance, diode is connected between the power supply lines. The reverse voltage across the high conductivity diode is less than that of any other diodes at a given current level, whereby only the high conductivity diode conducts substantial currents in the reverse direction.

Encapsulated light-emitting diode structure and array thereof

Abstract: A light-emitting diode including a casing with two flat outer light-emitting opposite parallel sides connected by a curved outer surface.

Extraction and focusing of intense ion beams from a magnetically insulated diode

Abstract: A magnetically insulated diode has been used to produce cylindrically converging intense proton beams. By providing electron neutralization along field lines, the beams can be propagated across the magnetic field to within 1 cm of the axis. Proton currents up to 5 kA have been propagated to achieve current densities up to 70 A/cm2. Divergences less than 3° have been achieved with new plasma anode designs. Calculations are presented on the extrapolation of magnetic diodes to achieve power densities needed for ion‐beam pellet‐fusion breakeven.

Silicon p−n insulator-metal (p-n-I-M) devices

Abstract: Silicon p-n-I-M devices with thin insulating layers ( thicknesses ⩽ 30 A ), named MTIS devices, have been developed. The two terminal device shows an S-shaped negative resistance characteristics similar to a Schockley diode (or p-n-p-n diode). Typically the threshold and sustaining voltages are 10 ∼ 15 and 1.3 ∼ 2 volts, respectively. The former however can be controlled by optical illumination. Turn-on time including delay is less than 2 nsec and turn-off time − 1 nsec or less. A thyristor-like device with its third terminal connected to the n-layer shows switching operation controllable by this terminal. A monolithic linear array of p-n-I-M diodes with 30 μm spacing operates as a shift register through coupling of adjacent diodes. Life of the two terminal devices recorded at present is over 1.5 × 104 hr. These devices can be applied to low power and high-speed electrical switching and also to optical switching and integrated logic circuits.

Pulsed room‐temperature operation of In1−xGaxP1−zAsz double heterojunction lasers at high energy (6470 Å, 1.916 eV)

Abstract: Pulsed room‐temperature operation of LPE In1−xGaxP1−zAsz double heterojunction (DH) laser diodes at short wavelength is described (Jth≲2×104 A/cm2, λ∼6470 A, heterobarrier ΔE∼137 meV). The differential quantum efficiency of these diodes is ηext∼5%, and is considered to be low because of large diode size, thick active region, probably some layer mismatch and growth defects, and relatively poor heat sinking. The temperature dependence of threshold current density (Jth∼J0 expT/T0, T0∼74 °K) is presented in the range 77–300 °K and is compared with similar diodes having smaller heterobarriers and which, as expected, exhibit poorer performance (smaller T0).

Infrared detection and mixing in heavily doped Schottky‐barrier diodes

Abstract: Transit‐time and series‐resistance effects in heavily doped Schottky‐barrier diodes operating in the thermionic mode are evaluated by applying the laws of vacuum tube electronics to the space‐charge region and by incorporating the treatment of the series‐resistance effect into the discussion. It is assumed that the field distribution in the space‐charge region is linear, that collisions in the space‐charge region can be neglected, and that the signals are so small thatr the equations of motion can be linearized. The case of uniform field distribution is also briefly dealt with; the results are not significantly different from the linear field case. At a frequency equal to three times the plasma frequency of the bulk semiconductor the detection and mixing efficiency is about 0.25 times the low‐frequency value. The effect of the high‐frequency conductance of the space‐charge region turns out to be quite small when the series‐resistance effect is taken into account; the performance is then determined by a single transit‐time factor ‖g (jω) ‖2 and a series‐resistance factor that is independent of transit time. The effect of tunneling on the device performance is discussed briefly. Satisfactory detection and mixing performance seems feasible for the 10–40‐μm wavelength range.

Schottky Barrier Betavoltaic Battery

Abstract: A new nuclear betavotaic battety is described. It uses a Schottky barrier in place of the more standard p-n junction diode, along with 147Pm metal film rather than Pm2O3 oxide as in the commercially available Betacel. Design details of the battery including measurement of absorption, conversion efficiency, thickness etc. as functions of & resistivity and other cell parameters are described. A prototype design is discussed and its performance assessed.

Investigation of the transition from tunneling to impact ionization multiplication in silicon p-n junctions☆

Abstract: White noise spectra of diodes breaking down between 1·5 and 5 V have been used to investigate the details of the transition from tunneling to avalanche breakdown in silicon p-n junctions. It is found that the transition and carrier multiplication in these junctions is dominated by the influence of the threshold energies for ionization. Because this influence is not explicitly taken into account in the existing theories of carrier multiplication and noise, they are not applicable to low breakdown voltage diodes. Consequently, a multiplication onset model and alternate schemes for calculating the DC multiplication and noise in low breakdown voltage diodes are developed. Analysis of the noise data indicates that the threshold energies for ionization depend slightly on junction widths and, for the diodes employed in this study, range between 1·66–1·9 eV for electrons and 1·79–2·04 eV for holes. The minimum distance between ionizing collisions is found to range from 190 to 240 A for electrons and 200 to 250 A for holes. Application of the threshold energies for ionization to the multiplication onset model permits evaluation of the doping densities on both sides of the step junctions. From it, it is determined that the solubility of aluminum in silicon is NA = 9·5 ± 0·5 × 1018 cm−3.

Interfacial states spectrum of a metal-silicon junction

Abstract: The interfacial states density has been explored as a function of energy over almost the whole of the forbidden gap for a MoSi junction, and over the upper half of the forbidden gap for a CrSi junction. The method used consisted of a study of the frequency variation of the differential capacitance at forward biased MoSi n , MoSi p and CrSi n diodes. The measurements were carried out over a frequency range of 10 Hz–500 kHz and between 77 and 300°K.

Lasing characteristics of distributed-feedback GaAs-GaAlAs diode lasers with separate optical and carrier confinement

Abstract: The lasing characteristics of separate-confinement-heterostructure (SCH-structure) distributed-feedback (DFB) diode lasers are examined theoretically and experimentally. Wave propagation in five-layer SCH waveguides is analyzed to estimate such parameters as the lasing wavelength, coupling constant, and external quantum efficiency. Spectral and modal behavior are studied in the experiment and compared with the theoretical predictions. Diodes are shown to lase in a single longitudinal mode with a definite polarization. Spectral width is about 300 MHz just above the threshold, and becomes wider with increased excitation level. An output power of 40 mW with an external quantum efficiency of 5 percent is obtained under CW operation.

Measuring and minimizing diode detector nonlinearity

Abstract: This paper describes two techniques for measuring the linearity of amplitude detectors in general, and for measuring the deviation from square-law E of point-contact diode detectors in particular. A general mathematical model is given for determining the RF input power as a function of the detector output voltage. It is shown how to choose the value and the temperature coefficient of the video load resistance to minimize E and make E independent of temperature.

Hole conduction in Si3N4 films on Si

Abstract: Dominant hole conduction is observed in thin Si3N4 films deposited on silicon with holes being injected from either aluminum or gold electrodes. Hole transport is confirmed by employing a shallow junction diode detector. Such a diode can serve also as excellent means for separating conduction currents from transient displacement currents under pulsed conditions.