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Percussive welding of metal-semiconductor contacts
A B S T R A C T S ON M I C R O E L E C T R O N I C S AND R E L I A B I L I T Y
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rather than float in a proportional band as in manual reset systems. Thus the temperature profile cannot drift. Further, the end zones respond immediately to minute adjustments, resulting in tighter profiles than ever before possible.
The conduction properties of Ge-GaAsl-zPz n-n heterojunctions. L. L. CHANG, Solid State Electronics 8, p. 721 (1965). n-type Ge has been grown epitaxially on GaAst%Pz substrates of 4 × 1017 cm -a donors at 360°C. The substrates have < 111 > orientation and a composition range of x ~ 0, 0.1 and 0.3. Junctions made with x : 0 or 0.1 exhibit diode behaviour that can be interpreted by the metal-semiconductor emission theory modified to take into account the effects of both electron tunnelling and voltage distribution between the semiconductors. The barrier heights have been found to be 0.62 and 0.53 V for the A- and B-surface of substrates with x : 0.1 and 0.50 V and 0.43 V correspondingly with x : 0. The apparent barriers at zero bias are smaller than these values by about 0.2 V due to tunnelling reduction. For substrates with x ~ 0.3, various measurements tend to suggest a structure of back-toback diodes. The effect of interface states, as likely produced by the relatively large lattice mismatch in this case ( > 1 per cent), is believed to be responsible for this structure. Solid state inductors. H. C. JOSEPHS,R. I. GEORGEand R. BILLETTE,Solid-State Electronics 8, p. 775 (1965). Previous analyses of inductive effects in common emitter transistor circuits are extended and new circuits are presented which exhibit larger inductive effects. These include circuits, for which there are no vacuum-tube equivalents, in which the transistor is operated above its c~---- 1 voltage. The mechanisms which limit the obtainable values of inductance and the ratio of reactance to resistance are described. Temperature stability data and methods of temperature compensation are presented. It is concluded that simple techniques can be used to obtain sufficient stability for many applications. Percussive welding of metal-semiconductor contacts. L. D. HECK and J. C. LOONEY, S C P and Solid State Technology, p. 11 (June 1965). The feasibility of applying percussive welding techniques to the fabrication of metal-semiconductor contacts is investigated. The theoretical and technological requirements of alloyed contacts were met by determining the parameters controlling the percussive welding process. The parameters were then optimized by the combination of theoretical and empirical methods. Both ohmic and rectifying contacts were fabricated by the percussive welding of gold and aluminium wires to silicon and germanium semiconductor samples. Study of the metal-oxide-semiconductor field-effect with insulating grid. C. JUND, Ann. Radiodlect., No. 81, pp. 212-232 (July 1965). Based on the results already obtained for field-effect
junction elements an attempt has been made to produce a theory of field effect elements with an insulating grid. The theoretical and experimental study of the capacities of the metal-oxide-semiconductor system has brought out the action of surface states at the dielectric-semiconductor interface. In view of the fact that the physical phenomenon responsible for current saturation in a field effect element appears to be the limit speed reached by the carriers in the channel, a system of equations was introduced in the ANALAC analogue comuter, this system of equations taking into account the limit speed phenomenon and the presence of sruface states. The curve giving the potential distribution in the channel has made it possible to work back to the electrical characteristics of the element. The results obtained are in good agreement with the experimental values.
The oxidation of silicon in dry oxygen. F. LUKESand E. SCHMIDT,ft. Phys. Chem. Solids 26, p. 1353 (1965). The oxidation of single-crystal silicon has been studied in dry oxygen in the temperature range 1050-1300°C. The oxide film thickness obeys a parabolic law as previously reported by other authors in this temperature range. The rate constant k 2 in the formula d ~ -~ k2t depends on temperature not exponentially as is usually estimated but obeys the formula k 2 ~: A ( T - - T o ) ~. Temperature dependence of conductivity of silicon-silicon dioxide interface. R. Y. DESHPANDE, Solid-State Electronics 8, p. 619 (1965). Conductivity of a silicon-silicon dioxide interface has been measured as a function of temperature. From the data the activation energies of the impurity levels introduced by the various ambient and heat treatments are estimated. Knowledge of surface charge
91
rather than float in a proportional band as in manual reset systems. Thus the temperature profile cannot drift. Further, the end zones respond immediately to minute adjustments, resulting in tighter profiles than ever before possible.
The conduction properties of Ge-GaAsl-zPz n-n heterojunctions. L. L. CHANG, Solid State Electronics 8, p. 721 (1965). n-type Ge has been grown epitaxially on GaAst%Pz substrates of 4 × 1017 cm -a donors at 360°C. The substrates have < 111 > orientation and a composition range of x ~ 0, 0.1 and 0.3. Junctions made with x : 0 or 0.1 exhibit diode behaviour that can be interpreted by the metal-semiconductor emission theory modified to take into account the effects of both electron tunnelling and voltage distribution between the semiconductors. The barrier heights have been found to be 0.62 and 0.53 V for the A- and B-surface of substrates with x : 0.1 and 0.50 V and 0.43 V correspondingly with x : 0. The apparent barriers at zero bias are smaller than these values by about 0.2 V due to tunnelling reduction. For substrates with x ~ 0.3, various measurements tend to suggest a structure of back-toback diodes. The effect of interface states, as likely produced by the relatively large lattice mismatch in this case ( > 1 per cent), is believed to be responsible for this structure. Solid state inductors. H. C. JOSEPHS,R. I. GEORGEand R. BILLETTE,Solid-State Electronics 8, p. 775 (1965). Previous analyses of inductive effects in common emitter transistor circuits are extended and new circuits are presented which exhibit larger inductive effects. These include circuits, for which there are no vacuum-tube equivalents, in which the transistor is operated above its c~---- 1 voltage. The mechanisms which limit the obtainable values of inductance and the ratio of reactance to resistance are described. Temperature stability data and methods of temperature compensation are presented. It is concluded that simple techniques can be used to obtain sufficient stability for many applications. Percussive welding of metal-semiconductor contacts. L. D. HECK and J. C. LOONEY, S C P and Solid State Technology, p. 11 (June 1965). The feasibility of applying percussive welding techniques to the fabrication of metal-semiconductor contacts is investigated. The theoretical and technological requirements of alloyed contacts were met by determining the parameters controlling the percussive welding process. The parameters were then optimized by the combination of theoretical and empirical methods. Both ohmic and rectifying contacts were fabricated by the percussive welding of gold and aluminium wires to silicon and germanium semiconductor samples. Study of the metal-oxide-semiconductor field-effect with insulating grid. C. JUND, Ann. Radiodlect., No. 81, pp. 212-232 (July 1965). Based on the results already obtained for field-effect
junction elements an attempt has been made to produce a theory of field effect elements with an insulating grid. The theoretical and experimental study of the capacities of the metal-oxide-semiconductor system has brought out the action of surface states at the dielectric-semiconductor interface. In view of the fact that the physical phenomenon responsible for current saturation in a field effect element appears to be the limit speed reached by the carriers in the channel, a system of equations was introduced in the ANALAC analogue comuter, this system of equations taking into account the limit speed phenomenon and the presence of sruface states. The curve giving the potential distribution in the channel has made it possible to work back to the electrical characteristics of the element. The results obtained are in good agreement with the experimental values.
The oxidation of silicon in dry oxygen. F. LUKESand E. SCHMIDT,ft. Phys. Chem. Solids 26, p. 1353 (1965). The oxidation of single-crystal silicon has been studied in dry oxygen in the temperature range 1050-1300°C. The oxide film thickness obeys a parabolic law as previously reported by other authors in this temperature range. The rate constant k 2 in the formula d ~ -~ k2t depends on temperature not exponentially as is usually estimated but obeys the formula k 2 ~: A ( T - - T o ) ~. Temperature dependence of conductivity of silicon-silicon dioxide interface. R. Y. DESHPANDE, Solid-State Electronics 8, p. 619 (1965). Conductivity of a silicon-silicon dioxide interface has been measured as a function of temperature. From the data the activation energies of the impurity levels introduced by the various ambient and heat treatments are estimated. Knowledge of surface charge