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Semivacancy pair in crystalline silicon
WORLD
ABSTRACTS
ON MICROELECTRONICS
being charged for electronic watches. As a result, semiconductor houses are only supplying limited quantities of low-power M O S i.c.s to the watchmakers.
Digital ICS + VOR = simpler navigation. I. Bm~IKSS. Electronics, 15 March (1971), p. 80. Integrated circuits are as yet seldom found in lightplane avionics, despite the radical improvements they have made in the performance and reliability of military avionics, and despite the size of the potential market--there are now 120,000 lightplanes in the U.S. alone, and their number is growing rapidly. However, a new converter-indicator for the standard international navigation system, known as the v.h.f, omnidirectional range (VOR) system, uses i.c.s almost exclusively. This design, in which the standard d'Arsonval meter indicator is replaced by a direct numeric readout using light-emitting diodes is smaller and lighter than conventional types, consumes less power and offers about a tenfold improvement in reliability. Further, it can be produced and sold for less than the least costly standard system.
Inside electronic watches: a m i c r o p o w e r m o v e ment. G. M. WALKER.Electronics, 12 April (1971), p. 97. Now that power consumption has been reduced to acceptable levels, a variety of bipolar and MOS counter/ divider/driver circuits offers greater accuracy and reliability than do mechanical approaches.
M o l y b d e n u m gates open the door to faster MOS m e m o r i e s . W. J. LAUGHTON. Electronics, 12 April (1971), p. 68. Gates of refractory moly are self-aligning,
7. S E M I C O N D U C T O R
INTEGRATED
S e m l v a c a n c y pair in crystalline silicon. B. J. MASTERS. Solid State Commun. 9 (1971), p. 283. A split configuration for the monovacancy in silicon, the semivacancy pair, is proposed. It is argued that the previously proposed "divacancy" should be reidentified as the semivacancy pair, and that it is this defect which is responsible for the diffusion of substitutional atoms in silicon.
Electronic properties of amorphous s e m i c o n d u c tors. J. STUKE.Proc. lOth. International Conf. on the Physics of Semiconductors. (CONF-700801), Massachusetts Institute of Technology Cambridge, Mass., U.S.A., 1721 August (1970). The change of optical and electrical properties of semiconductors, going from the crystalline to the amorphous state, is reviewed. The structure in the spectra of the optical constants is mainly smeared out. For some materials in addition selective changes of single maxima are observed. T h e alternation of the electrical properties is characterized by an increase of the electrical bandgap at the transition to the disordered state. Moreover, the magnitude of the extrinsic conduction is strongly reduced. This behaviour and recent measurement of magnetoresistance, piezoresistance and thermoelectric power are discussed in terms of existing models.
AND RELIABILITY
253
have very low sheet resistance, and cause minimal voltage drops across electrodes; these benefits add up to a 5-mHz shift register that is the fastest MOS device in production.
Low cost digital I.C.'s yield three-phase slgnal generator. R. P. BISEY. Microeleetronics 3, No. 9 (1970), p. 19. This article describes a compact and economical three-phase signal generator whose phase characteristics are completely independent of frequency. Three digital i.c.s totalling about £2.50 in cost, generate three independent square wave signals of the same frequency, and are phased 120 degrees with respect to each other. These signals can then be amplified to power three-phase devices.
Divide frequencies by an integer. R. W. BURHANS, R. K. BLAKE, Electron. Des. 3, 4 February (1971), p. 42. The division of clock frequencies by any integral divisor can be accomplished by selectively controlling the input signals to a common pulse-gated ripple counter. T h e number of components is reduced in comparison to other methods of frequency division because only one monostablegate generator is needed. This advantage is most apparent for large input/output frequency ratios that would otherwise require many external gates. Either T T L or R T L logic can be used for the circuit, and the method is easily adaptable to M S I or conventional manufacturing. For example, ten flip-flops and four dual gates, either deposited on one M S I chip or assembled from i.c.s on to a circuit card, can provide a low-cost, adjustable divider to cover the entire audio range from one clock frequency.
CIRCUITS, DEVICES AND MATERIALS
Electron tunneling in clean Al-insulator-normal m e t a l junction. T. T. CHEN and J. G. ADLER. Solid State Commun. 8 (1970), p.9 1965. T h e metal phonon peaks have been observed in the derivative of the conductance of clean Al-insulator-metal film junctions using different counter electrodes. Most of the clean junctions show a parabolic tunneling conductance with minimum offset from zero bias. A zero bias anomaly was observed for all these aluminum based junctions.
Metal-insulator transition metal oxides. T. M. RICE, D. B. MCWHAN and W. F. BRINKMAN. Proc. lOth International Conf. on the Physics of Semiconductors (CONF-700801). Massachusetts Institute of Technology, Cambridge, Mass., U.S.A., 17-21 August (1970). The electrical and magnetic properties of the transition metal oxides are reviewed. Several empirical trends for this class of materials are commented on. T h e generalized phase diagram for the transition in V~Os is described and its interpretation in terms of a Mott transition is discussed. A review of the TizVx-xOz mixed oxide sequence suggests that a localized description of the insulating phase of VO2 is appropriate. It is shown that a state with
ABSTRACTS
ON MICROELECTRONICS
being charged for electronic watches. As a result, semiconductor houses are only supplying limited quantities of low-power M O S i.c.s to the watchmakers.
Digital ICS + VOR = simpler navigation. I. Bm~IKSS. Electronics, 15 March (1971), p. 80. Integrated circuits are as yet seldom found in lightplane avionics, despite the radical improvements they have made in the performance and reliability of military avionics, and despite the size of the potential market--there are now 120,000 lightplanes in the U.S. alone, and their number is growing rapidly. However, a new converter-indicator for the standard international navigation system, known as the v.h.f, omnidirectional range (VOR) system, uses i.c.s almost exclusively. This design, in which the standard d'Arsonval meter indicator is replaced by a direct numeric readout using light-emitting diodes is smaller and lighter than conventional types, consumes less power and offers about a tenfold improvement in reliability. Further, it can be produced and sold for less than the least costly standard system.
Inside electronic watches: a m i c r o p o w e r m o v e ment. G. M. WALKER.Electronics, 12 April (1971), p. 97. Now that power consumption has been reduced to acceptable levels, a variety of bipolar and MOS counter/ divider/driver circuits offers greater accuracy and reliability than do mechanical approaches.
M o l y b d e n u m gates open the door to faster MOS m e m o r i e s . W. J. LAUGHTON. Electronics, 12 April (1971), p. 68. Gates of refractory moly are self-aligning,
7. S E M I C O N D U C T O R
INTEGRATED
S e m l v a c a n c y pair in crystalline silicon. B. J. MASTERS. Solid State Commun. 9 (1971), p. 283. A split configuration for the monovacancy in silicon, the semivacancy pair, is proposed. It is argued that the previously proposed "divacancy" should be reidentified as the semivacancy pair, and that it is this defect which is responsible for the diffusion of substitutional atoms in silicon.
Electronic properties of amorphous s e m i c o n d u c tors. J. STUKE.Proc. lOth. International Conf. on the Physics of Semiconductors. (CONF-700801), Massachusetts Institute of Technology Cambridge, Mass., U.S.A., 1721 August (1970). The change of optical and electrical properties of semiconductors, going from the crystalline to the amorphous state, is reviewed. The structure in the spectra of the optical constants is mainly smeared out. For some materials in addition selective changes of single maxima are observed. T h e alternation of the electrical properties is characterized by an increase of the electrical bandgap at the transition to the disordered state. Moreover, the magnitude of the extrinsic conduction is strongly reduced. This behaviour and recent measurement of magnetoresistance, piezoresistance and thermoelectric power are discussed in terms of existing models.
AND RELIABILITY
253
have very low sheet resistance, and cause minimal voltage drops across electrodes; these benefits add up to a 5-mHz shift register that is the fastest MOS device in production.
Low cost digital I.C.'s yield three-phase slgnal generator. R. P. BISEY. Microeleetronics 3, No. 9 (1970), p. 19. This article describes a compact and economical three-phase signal generator whose phase characteristics are completely independent of frequency. Three digital i.c.s totalling about £2.50 in cost, generate three independent square wave signals of the same frequency, and are phased 120 degrees with respect to each other. These signals can then be amplified to power three-phase devices.
Divide frequencies by an integer. R. W. BURHANS, R. K. BLAKE, Electron. Des. 3, 4 February (1971), p. 42. The division of clock frequencies by any integral divisor can be accomplished by selectively controlling the input signals to a common pulse-gated ripple counter. T h e number of components is reduced in comparison to other methods of frequency division because only one monostablegate generator is needed. This advantage is most apparent for large input/output frequency ratios that would otherwise require many external gates. Either T T L or R T L logic can be used for the circuit, and the method is easily adaptable to M S I or conventional manufacturing. For example, ten flip-flops and four dual gates, either deposited on one M S I chip or assembled from i.c.s on to a circuit card, can provide a low-cost, adjustable divider to cover the entire audio range from one clock frequency.
CIRCUITS, DEVICES AND MATERIALS
Electron tunneling in clean Al-insulator-normal m e t a l junction. T. T. CHEN and J. G. ADLER. Solid State Commun. 8 (1970), p.9 1965. T h e metal phonon peaks have been observed in the derivative of the conductance of clean Al-insulator-metal film junctions using different counter electrodes. Most of the clean junctions show a parabolic tunneling conductance with minimum offset from zero bias. A zero bias anomaly was observed for all these aluminum based junctions.
Metal-insulator transition metal oxides. T. M. RICE, D. B. MCWHAN and W. F. BRINKMAN. Proc. lOth International Conf. on the Physics of Semiconductors (CONF-700801). Massachusetts Institute of Technology, Cambridge, Mass., U.S.A., 17-21 August (1970). The electrical and magnetic properties of the transition metal oxides are reviewed. Several empirical trends for this class of materials are commented on. T h e generalized phase diagram for the transition in V~Os is described and its interpretation in terms of a Mott transition is discussed. A review of the TizVx-xOz mixed oxide sequence suggests that a localized description of the insulating phase of VO2 is appropriate. It is shown that a state with