Showing papers on "Junction temperature published in 1981"
TL;DR: In this paper, the temporal dependence of the frequency shift in a single-mode semiconductor laser was measured and compared with calculations based on solutions to the thermal diffusion equation, and the effects of carrier density change, thermal diffusion in the semiconductor, and heat sink thermal resistance were identified.
Abstract: The temporal dependence of the frequency shift in a current-modulated single-mode semiconductor laser is measured and compared with calculations based on solutions to the thermal diffusion equation. The effects of carrier density change, thermal diffusion in the semiconductor, and heat sink thermal resistance are identified.
27 citations
TL;DR: In this paper, active layer temperature stabilization in semiconductor laser diodes is treated theoretically and numerically, and conditions required for the control circuit are analyzed theoretically and quantitatively.
Abstract: Active layer temperature stabilization in semiconductor lasers is treated theoretically. Laser diodes are assumed to be mounted on a submount which is in contact with a heat sink block. The active layer temperature fluctuation signal is fed back to a Peltier device, an injection current, or a resistor layer in the chip. Active layer temperature stability and conditions required for the control circuit are analyzed theoretically and numerically.
12 citations
TL;DR: Hall effect and electrical resistivity measurements were carried out on samples of heavily doped n-type silicon germanium alloys during high temperature isothermal heat treatment in this paper, where the samples were initially annealed at 1300 K, quenched to room temperature and then subjected to short-term heat treatment at temperatures of 630 K, 825 K, 980 K and 1040 K.
7 citations
Patent•
27 Apr 1981
TL;DR: In this paper, a push-pull type amplifying circuit using bipolar transistors was proposed to obtain the output without distortion independently of the base-to-emitter voltage of the input and amplifying transistors, by keeping the junction temperature of them constant, in the push pull type Amplifying circuit.
Abstract: PURPOSE:To obtain the output without distortion independently of the base-to- emitter voltage of the input and amplifying transistors, by keeping the junction temperature of them constant, in the push-pull type amplifying circuit using bipolar transistors CONSTITUTION:The amplifier 1 has npn-TRQ2 taking the emitter output of pnp- transistor (TR)Q1 of emitter follower constitution as the base input, and the emitter of TRQ2 is connected to the negative power supply -B3 via the emitter resistor R1 The collector of TRQ1 is connected to the negative power supply -B3 and the current Miller circuit 3 which supplies a given ratio of currents I1, I2 to both the TRsQ1, Q2 respectively, is provided When the junction temperature of TRsQ1, Q2 is kept constant, the difference of the base-to-emitter voltage VBE is a given value gamma, allowing to keep constant the output voltage VOUT1 of TRQ4 and similarly the output VOUT2 of TRQ8 Thus, the output voltage without distortion can be obtained independently of the voltage VBE by synthesizing both the outputs VOUT1, VOUT2
2 citations
TL;DR: In this article, the problem of asymmetric heating of a plate in a medium with variable temperature in the presence of an internal heat source, the power of which is dependent on temperature and time, is considered.
Abstract: The problem of asymmetric heating of a plate is considered in a medium with variable temperature in the presence of an internal heat source, the power of which is dependent on temperature and time.
2 citations
Proceedings Article•
01 Jan 1981TL;DR: In this article, a spacecraft system study showed that an optimum hot junction temperature is in the range of 1500 K for advanced nuclear reactor technology combined with thermoelectric conversion, but the performance is marginal.
Abstract: Preliminary results from a spacecraft system study show that an optimum hot junction temperature is in the range of 1500 K for advanced nuclear reactor technology combined with thermoelectric conversion. Advanced silicon germanium thermoelectric conversion is feasible if hot junction temperatures can be raised roughly 100 C or if gallium phosphide can be used to improve the figure of merit, but the performance is marginal. Two new classes of refractory materials, rare earth sulfides and boron-carbon alloys, are being investigated to improve the specific weight of the generator system. Preliminary data on the sulfides have shown very high figures of merit over short temperature ranges. Both n- and p-type doping have been obtained. Pure boron-carbide may extrapolate to high figure of merit at temperatures well above 1500 K but not lower temperature; n-type conduction has been reported by others, but not yet observed in the JPL program. Inadvertant impurity doping may explain the divergence of results reported.
1 citations
Patent•
02 Oct 1981
TL;DR: In this paper, an insert foil of pure titanium or titanium alloy which is softer than the base metal at the junction temperature is inserted into the junction region between corrugate panel 11 and skin panel 12, in production of the door and so on of the airplane.
Abstract: PURPOSE:To form a joint part superior in strength on a titanium alloy sheet metal part by comparatively low-temperature diffused junction, by interposing an insert foil softer than a base metal for junction of the titanium alloy plate. CONSTITUTION:For diffused junction of titanium alloy plate materials, the insert foil of pure titanium or titanium alloy which is softer than the base metal at the junction temperature is inserted into the junction region between corrugate panel 11 and skin panel 12, for example, in production of the door and so on of the airplane. Next, diffused junction is performed with the junction temperature and junction pressure adapted to the quality. This insert foil does not disappear and is left after completion of junction. By this method, the lap joint which is superior in corrosion resistance and strength and has stable dimensions and form is formed on the titanium alloy sheet metal parts.
27 Feb 1981
TL;DR: In this paper, a bridge type double-quartz-standoff diode package has been developed and successively used for frequency up to 255 GHz and a phase-locked source was developed to achieve frequency stabiliza- tion at 217 GHz.
Abstract: This paper summarizes the recent state-of-the-art results in silicon IMPATT sources beyond 100 GHz. A bridge type double-quartz-standoff diode package has been developed and success fully used for frequency up to 255 GHz. Power combining techniques have been demonstrated to incorporate several diodes in a circuit that combines the power efficiently at 140 GHz and 217 GHz. Finally, a phase-locked source has been developed to achieve frequency stabiliza tion at 217 GHz.IntroductionOver the past several years, the increasing demand in millimeter-wave system has resulted in significant progress in the silicon IMPATT source development beyond 100 GHz,1-6 the emphasis of this development was mainly concentrated on the atmospheric windows at 140 GHz and 217 GHz. This paper reports the recent progress in output power achieved with IMPATT diodes and combiners at frequencies beyond 100 GHz.In pulsed operation, peak output powers of 4.4 watts at 140 GHz and 1 watt at 217 GHz have been achieved from our best diodes. In the combiner, peak output power of 9.2 watts has been demonstrated from a four-diode combiner at center frequency of 139.3 GHz. Preliminary result of 1.08 watt peak output power at a center frequency of 198 GHz has also been achieved from a two-diode combiner. The diodes were operated at 100-ns pulsewidth with 25 KHz pulse repetition frequency.In CW operation, an output power of 50 mW has been demonstrated at 245 GHz and 12 mW at 255 GHz. A highly stable phase-locked oscillator for coherent radar application was also developed at 217 GHz for the first time.Device DevelopmentTheoretically the double-drift diode provides high power and efficiency capabilities, as well as high device impedance for easier circuit matching to achieve optimum performance. However, the double-drift diode requires more complicated processing than single-drift diode. Multiple-layer structures have to be fabricated using multiple epitaxy or ion-implantation techniques. Both techniques are subject to some degradation as a result of straggling effects in the vicinity of the p-n junction as shown in Figure 1. For low frequency diodes the straggling grading is not significant since the grading portion is small compared with total epi-thickness. The widening of the active region causes a slight downward shift in the frequency where the negative conductance peaks. For high frequency diodes, the epi-thickness is only on the order of a few tenths of a micron. Consequently the straggling induced pro file grading at the p-n junction will cause performance degradation.Because of these straggling effects, most state-of-the-art results at high frequencies (above 100 GHz) have been achieved in the single-drift structure. Molecular Beam Epitaxy (MBE) can eventually be used to overcome the straggling effects and to improve the double- drift diode performance. Therefore, the single-drift structure is attractive in terms of its ease of fabrication.The theoretical design of silicon IMPATT diodes for a given frequency is carried out with a small-signal computer analysis.7 Strictly speaking, the effects of tunneling current, dead spaces and diffusion current become important at high frequencies and should be included in the computer program. However, a preliminary design can be generated with a computer analysis neglecting these effects. For a specified current density, junction temperature and the junction doping profile, the small-signal computer program calculates and plots the dc electric field as a function of distance. The computer program then uses this dc solution to calculate the device small-signal RF conductance and susceptance per unit area, and the device Q, as a function of frequency for a specified frequency range. The design parameters of the diodes are selected when the device Q versus frequency display its maximum near the desired frequency of operation. Table I summarizes the diode design parameters for 140 GHz and 217 GHz in pulsed operation.