High-performance InP/InGaAs heterojunction bipolar transistors with highly carbon-doped base grown by chemical beam epitaxy

InP/In/sub 0.53/Ga/sub 0.47/As heterojunction bipolar transistors (HBTs) using a highly carbon-doped base are reported. High carbon doping has been achieved by chemical beam epitaxy (CBE). The resulting hole concentration in the carbon-doped base is as high as 7*10/sup 19//cm/sup 3/. To the authors' knowledge, this is the highest doping level reported using carbon. HBTs with a 20 AA spacer layer exhibited nearly ideal I-V characteristics with collector and base current ideality factor of 1.018 and 1.037, respectively. Current gain and breakdown voltage BV/sub CEO/ were 7 and 6 V, respectively.<>     

Micron-image transfer system with brightness amplifier in gold-vapor laser

A gas-discharge gold-vapor laser on self-terminating transitions with operating wavelength λ=312.2 nm has been used to develop a highly efficient system for image transfer. An optical scheme and all its parameters have been chosen optimal for image quality. It has been found both theoretically and experimentally that the best results on micron-structure image transfer are obtained with 2–5-times image reduction. Various types of masks have been used. A 1-µm structure has been resolved due to the choice of optimal exposure time of 10 ms under a period of pulse repetition (0.6 – 0.8) ms; in this case, the minimal fringe dimension was ≈2 µm with an image dimension of 2 mm for a laser tube 1.8 cm in diameter.     

Ion Beam Driven Ion Cyclotron Double Layers

We present here a self consistent theory of small amplitude double layers associated with electrostatic ion cyclotron waves in a plasma containing hot electrons, cold ions and traversed by an ion beam. It has been shown that compressive type of double layers solution exists when θ_b (beam temperature) < α_b (beam concentration) < 1.     

Strain compensated InGaAs-GaAsP-InGaP laser

The performance characteristics of InGaAs-GaAsP-InGaP strain compensated laser emitting near 1 /spl mu/m are reported. The ridge waveguide lasers have room temperature threshold current of 18 mA and differential quantum efficiency of 0.45 W/A/facet. The linewidth enhancement factor is smaller and gain coefficient is larger for these strain compensated lasers compared to that for conventional strained layer laser. This may be due to higher effective compressive strain in the light emitting layer of these devices which reduces the effective mass. The observed larger gain coefficient is consistent with the measured larger relaxation oscillation frequency of these lasers compared to that for a conventional strained layer laser.     

A mathematical model of a class of problems for the transport of a mixture in air

An analytic solution of a class of boundary-value problems of mathematical physics describing the transport of a mixture in the atmosphere is considered. To solve these problems we apply the substitution method and the Fourier method. The solution of a boundary problem describing the process of contamination of the atmosphere by various substances is presented in the form of a series. The result obtained is useful for the solution of problems concerning the protection of the atmosphere.Translated fromVychislitel'naya i Prikladnaya Matematika, No. 69, pp. 87–90, 1989.     

GaInP/GaAs HBTs for high-speed integrated circuit applications

The use of GaInP/GaAs heterojunction bipolar transistors (HBTs) for integrated circuit applications is demonstrated. The discrete devices fabricated showed excellent DC characteristics with low V_ce offset voltage and very low temperature sensitivity of the current gain. For a non-self-aligned device with a 3-μm×1.4-μm emitter area, f_T was extrapolated to 45 GHz and f_max was extrapolated to 70 GHz. The measured 1/f noise level was 20 dB better than that of AlGaAs HBTs and comparable to that of low-noise silicon bipolar junction transistors, and the noise bump (Lorentzian component) was not observed. The fabricated gain block circuits showed 8.5 dB gain with a 3-dB bandwidth of 12 GHz, and static frequency dividers (divide by 4) were operable up to 8 GHz     

Infrared reflection spectra in contactless nondestructive measurements of the electron density and mobility in indium phosphide

On the basis of numerical calculations and experimental studies we analyze the possibilities of measuring the electrophysical parameters of indium phosphide by means of infrared reflection spectra at wavelengths ranging from 5 to 200 m. We demonstrate that contactless nondestructive measurements of the electron density in the range 10¹⁶–10²⁰ cm^–3 can be made with a relative error not exceeding 15%, and of mobility with a relative error not exceeding 25%. A nomogram method is presented for rapid conversion of data from infrared reflection spectra into the parameters being measured.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 22–27, January, 1988.