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Package piggybacks standard E-PROM to emulate one-chip microcomputer
548
World Abstracts on Microelectronics and Reliability
14-bit s-d converter gets smaller. PAMELA HAMILTON. Electronics p. 116 (31 January 1980). Synchro-to-digital converter uses two custom LSI chips and four standard ICs in a double-width dual in-line package to miniaturize hybrid design. Peripheral controller tarns to 12L JEFFREY M. WISTEDand DAVID E. TETZLAFF. Electronics p. 93 (31 January 1980).
Four chips and a ZS0 microprocessor make controller programmable for a variety of peripherals.
Package piggybacks standard E-PROM to emulate one-chip microcomputer. STEVE GER~N. Electronics p. 89 (31 January 1980). 24-pin socket on processor's back accommodates 2716 or 2732 E-PROMs, replaces external pc boards for better emulation of 3870 family.
7. SEMICONDUCTOR INTEGRATED CIRCUITS, DEVICES AND MATERIALS Influence of the growth parameters in GaAs vapour phase epitaxy. J. M. DURAND. Philips J. Res. 34, (5/6) 177 (1979). The growth of gallium arsenide by vapour phase deposition according to the arsenic trichloride transport method has been studied by measurement of the growth rate as a function of the principal growth parameters, which were varied within a wide range. The experimental part consists of a study of (i) the influence of the supersaturation at the source, of the deposition temperature, and of the input partial pressure of arsenic trichloride, (ii) the investigation of the (ll0) plane and vicinal planes as possible growth planes, (iii) the anisotropy in vapour phase growth corresponding to unusual growth conditions, namely low temperature and high partial pressure of arsenic trichloride. An attempt was made to interpret the experimental results in accordance with the theoretical model of Cadorett). Ultraviolet photoelectron investigation of Si (lll)/Au interface at high temperatures. I. ABBATI,L. BRAICOVICHand A. FRANCIOSI. Solid-St. Comms. 33, 881 (1980). The intermixed region at the Si(lll)/Au interface has been studied with ultraviolet photoemission (he = 21.2 eV and hv = 10.2 eV) as a function of thermal treatment of the junction (from RT up to 550°C). At increasing temperatures a chemically driven intermixing takes place. The results depend markedly on the temperature up to "--350--400°C. At higher temperatures a stable interface phase which behaves as a small gap semiconductor has been formed. Dependence of the saturation intensity of p-type germanium on impurity concentration and residual absorption at 10.59 ~m. R. B. JAMESand D. L. SMITH. Solid-St. Communs. 33, 395 0980). We present a calculation of the saturation intensity Is of p-Ge at 10.59 izm as a function of the impurity concentration. The effect of residual absorption is calculated and found to be important in the interpretation of experiments for intensities much greater than Is. Observation of lifetime controlling recombination centres in silicon power devices. D. H. PAXMAN and K. R. WHIGHT. Solid-St. Electron. 23, 129 (1980). A survey has been made by D.L.T.S. of the recombination centres present in n and p base silicon power devices. By comparing this data with high injection lifetime measurements, it has been possible to show that two of the levels observed have high capture cross sections and can control the lifetimes in a processed device. Topological and experimental analysis of stationary behaviour of transferred-electron devices with nonuniform geometry. H. TATENO and S. KATAOKA. IEEE Proc. 127, (I, 1) 9 (February 1980). A study is made of topological and experimental analysis of stationary behaviour of transferred-electron devices of uniform doping concentration with nonuniform geometry. Such an analysis is useful in the understanding and estimating of the static characteristics of GaAs m.e.s.f.e,t.s, microwave amplifiers and fast switching devices. It is shown that it is possible for the devices to exhibit negative conductance, including switching between terminals, provided that the cross-sectional
area increases steeply toward the anode, and the doping concentration is higher than a critical value; and that this results from the formation of a stationary high-field domain around the expanded part. The theoretical result is experimentally confirmed with GaAs devices.
Ohmic contacts in GaAs. M. N. YODER. Solid-St. Electron. 23, 117 (1980). Ohmic contacts of n-type GaAs can be reproducibly made to exhibit specific contact resistivities less than 1 x 1 0 - 6 ~ - cm -2. To do this requires an understanding of the physics involved, a knowledge of the history of previous treatment of the GaAs wafer surface, and processing techniques which are compatible with precisely controlled donor impurit)' site location determination. The present paper correlates the electrical effects observed in several significant recent developments with theory and interface chemistry to provide workers in the field with a physical understanding of what is essential for reproducible, effective, and reliable ohmic contacts. A Thomas-Fermi description of the screening around the vacancy in silicon: charge state dependence. M. LANNOO and G. ALLAN. Solid-St. Comms. 33, 293 (1980). The usefulness of a Thomas-Fermi description of screening around defect centers in covalent systems is analyzed in some detail. It is first applied to the derivation of a very simple analytical expression for the q dependent dielectric constant in very good agreement with previous more elaborate calculations. The case of strong perturbations is then discussed together with the inclusion of an exchange correlation potential in a local density form. A detailed application is made in the neutral vacancy case leading to a self consistent potential in surprisingly good agreement with recent numerical calculations. An extension to other charge states of the vacancy is finally proposed and the corresponding contribution to the vacancy potential is calculated.
Time resolved photoluminescence near the "band gap" in amorphous silicon. S. KURITA, W. CZAJA and S. KINMOND. Solid-St. Comms. 32, 879 (1979). Two broad luminescence bands in weakly hydrogenated (glow discharge) undoped amorphous silicon have been observed using time resolved spectroscopy on a nanosecond timescale. Whereas the luminescence decay of the low energy band has been found to be sample independent, the peak position of the luminescence does show a sample dependence. We propose an intrinsic origin of this luminescence. Swirl defects in silicon single crystals. JUN-ICHI CHIKAWA and SHIGEO YOSHIKAWA. Solid-St. Technol. p. 65 (January 1980). The deleterious effects of swirl defects are outlined and defect investigations are reviewed. Swirl defect formation is examined by in-situ x-ray observation employing closed-circuit TV. The relationship between liquid drop formation and crystal perfection is studied. Conditions for the growth of perfect crystals are suggested.
Impurity interaction and the donor-acceptor recombination in semiconductors. J. GOLr~ and H. STOLL. Solid-St. Comms. 32, 479 (1979). The energy spectrum and the
World Abstracts on Microelectronics and Reliability
14-bit s-d converter gets smaller. PAMELA HAMILTON. Electronics p. 116 (31 January 1980). Synchro-to-digital converter uses two custom LSI chips and four standard ICs in a double-width dual in-line package to miniaturize hybrid design. Peripheral controller tarns to 12L JEFFREY M. WISTEDand DAVID E. TETZLAFF. Electronics p. 93 (31 January 1980).
Four chips and a ZS0 microprocessor make controller programmable for a variety of peripherals.
Package piggybacks standard E-PROM to emulate one-chip microcomputer. STEVE GER~N. Electronics p. 89 (31 January 1980). 24-pin socket on processor's back accommodates 2716 or 2732 E-PROMs, replaces external pc boards for better emulation of 3870 family.
7. SEMICONDUCTOR INTEGRATED CIRCUITS, DEVICES AND MATERIALS Influence of the growth parameters in GaAs vapour phase epitaxy. J. M. DURAND. Philips J. Res. 34, (5/6) 177 (1979). The growth of gallium arsenide by vapour phase deposition according to the arsenic trichloride transport method has been studied by measurement of the growth rate as a function of the principal growth parameters, which were varied within a wide range. The experimental part consists of a study of (i) the influence of the supersaturation at the source, of the deposition temperature, and of the input partial pressure of arsenic trichloride, (ii) the investigation of the (ll0) plane and vicinal planes as possible growth planes, (iii) the anisotropy in vapour phase growth corresponding to unusual growth conditions, namely low temperature and high partial pressure of arsenic trichloride. An attempt was made to interpret the experimental results in accordance with the theoretical model of Cadorett). Ultraviolet photoelectron investigation of Si (lll)/Au interface at high temperatures. I. ABBATI,L. BRAICOVICHand A. FRANCIOSI. Solid-St. Comms. 33, 881 (1980). The intermixed region at the Si(lll)/Au interface has been studied with ultraviolet photoemission (he = 21.2 eV and hv = 10.2 eV) as a function of thermal treatment of the junction (from RT up to 550°C). At increasing temperatures a chemically driven intermixing takes place. The results depend markedly on the temperature up to "--350--400°C. At higher temperatures a stable interface phase which behaves as a small gap semiconductor has been formed. Dependence of the saturation intensity of p-type germanium on impurity concentration and residual absorption at 10.59 ~m. R. B. JAMESand D. L. SMITH. Solid-St. Communs. 33, 395 0980). We present a calculation of the saturation intensity Is of p-Ge at 10.59 izm as a function of the impurity concentration. The effect of residual absorption is calculated and found to be important in the interpretation of experiments for intensities much greater than Is. Observation of lifetime controlling recombination centres in silicon power devices. D. H. PAXMAN and K. R. WHIGHT. Solid-St. Electron. 23, 129 (1980). A survey has been made by D.L.T.S. of the recombination centres present in n and p base silicon power devices. By comparing this data with high injection lifetime measurements, it has been possible to show that two of the levels observed have high capture cross sections and can control the lifetimes in a processed device. Topological and experimental analysis of stationary behaviour of transferred-electron devices with nonuniform geometry. H. TATENO and S. KATAOKA. IEEE Proc. 127, (I, 1) 9 (February 1980). A study is made of topological and experimental analysis of stationary behaviour of transferred-electron devices of uniform doping concentration with nonuniform geometry. Such an analysis is useful in the understanding and estimating of the static characteristics of GaAs m.e.s.f.e,t.s, microwave amplifiers and fast switching devices. It is shown that it is possible for the devices to exhibit negative conductance, including switching between terminals, provided that the cross-sectional
area increases steeply toward the anode, and the doping concentration is higher than a critical value; and that this results from the formation of a stationary high-field domain around the expanded part. The theoretical result is experimentally confirmed with GaAs devices.
Ohmic contacts in GaAs. M. N. YODER. Solid-St. Electron. 23, 117 (1980). Ohmic contacts of n-type GaAs can be reproducibly made to exhibit specific contact resistivities less than 1 x 1 0 - 6 ~ - cm -2. To do this requires an understanding of the physics involved, a knowledge of the history of previous treatment of the GaAs wafer surface, and processing techniques which are compatible with precisely controlled donor impurit)' site location determination. The present paper correlates the electrical effects observed in several significant recent developments with theory and interface chemistry to provide workers in the field with a physical understanding of what is essential for reproducible, effective, and reliable ohmic contacts. A Thomas-Fermi description of the screening around the vacancy in silicon: charge state dependence. M. LANNOO and G. ALLAN. Solid-St. Comms. 33, 293 (1980). The usefulness of a Thomas-Fermi description of screening around defect centers in covalent systems is analyzed in some detail. It is first applied to the derivation of a very simple analytical expression for the q dependent dielectric constant in very good agreement with previous more elaborate calculations. The case of strong perturbations is then discussed together with the inclusion of an exchange correlation potential in a local density form. A detailed application is made in the neutral vacancy case leading to a self consistent potential in surprisingly good agreement with recent numerical calculations. An extension to other charge states of the vacancy is finally proposed and the corresponding contribution to the vacancy potential is calculated.
Time resolved photoluminescence near the "band gap" in amorphous silicon. S. KURITA, W. CZAJA and S. KINMOND. Solid-St. Comms. 32, 879 (1979). Two broad luminescence bands in weakly hydrogenated (glow discharge) undoped amorphous silicon have been observed using time resolved spectroscopy on a nanosecond timescale. Whereas the luminescence decay of the low energy band has been found to be sample independent, the peak position of the luminescence does show a sample dependence. We propose an intrinsic origin of this luminescence. Swirl defects in silicon single crystals. JUN-ICHI CHIKAWA and SHIGEO YOSHIKAWA. Solid-St. Technol. p. 65 (January 1980). The deleterious effects of swirl defects are outlined and defect investigations are reviewed. Swirl defect formation is examined by in-situ x-ray observation employing closed-circuit TV. The relationship between liquid drop formation and crystal perfection is studied. Conditions for the growth of perfect crystals are suggested.
Impurity interaction and the donor-acceptor recombination in semiconductors. J. GOLr~ and H. STOLL. Solid-St. Comms. 32, 479 (1979). The energy spectrum and the