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Low frequency excess noise in SOS MOS FET's
762
World Abstracts on Microelectronics and Reliability
main problems in the development of planar MOS components are discussed. In the end, the various GaAs logic kinds are compared with regard to the attained parameters, to this end, a classification of the known logic circuits on silicon basis is made.
Low frequency excess noise in SOS M O S FET's. S. T. Hsu. RCA Rev. 41, 577 (December 1980). Noise in SOS fieldeffect transistors has been investigated in the 20 Hz to 1 M H z frequency range. The measurements were made with frequency, drain bias voltage, gate bias voltage, and temperature as parameters. The low-frequency excess noise source was identified as electron trap states in the thin silicon film. The electron trap states are located at 0.65 eV below the edge of the conduction band. The effective barrier height of the electron trap state was found to decrease with increasing drain bias voltage. The experimental results also indicate that in thin silicon films grown on sapphire substrates, the densities of hole trap states and generation recombination centers are very small compared to that of electron trap states.
Luminescence and lattice defects in Cu In S 2. G. MASSE, N. LAHLOU and C. BUTTI. J. Phys. Chem. Solids 42, 449 (1981). We have studied the cathodoluminescence of single crystals of Cu In S 2 obtained by iodine chemical transport. As grown crystals annealed in In, S, (In + S), or in vacuum, were used. Two types of spectrum were observed, one for n type crystals due to S vacancies, and the other for p type or compensated crystals, which is interpreted as donor-acceptor pair transitions (determined by Time Resolved Spectroscopy) between the S vacancy (donor ~ 90 meV) and the Cu vacancy (acceptor~45meV), and by the corresponding free-tobound transitions.
Semiconductor industry silicon: physical and thermodynamic properties. CARL L. YAWS, LARRY L. DICKENS, RALPH LUTWACK and GEORGE HSU. Solid-St. Technol. 87 (January 1981 ). Pertinent physical and thermodynamic properties are presented for silicon which has important and diverse uses in the semiconductor industry; in integrated circuits, in power devices, and in photoelectric solar cells. The data includes critical properties, vapor pressure, heat of vaporization, heat of sublimation, heat capacity, density, surface tension, viscosity, and thermal conductivity.
Diffusion theory of the steady-state flow of minority-carrier current through the Schottky barrier. STANISLAW SIKORSKt. Electron Technol. 12 (3) 13 (1979). The paper presents a generalized version of the Scharfetter theory of Schottky
8. T H I C K -
AND
THIN-FILM
COMPONENTS,
Failure analysis techniques applied to expoxy encapsulated thick-film hybrids. ALAN G. BROWN. Solid-St. Technol. 136 (February 1981). Failure analysis was performed on a number of defective thick-film voltage regulator modules widely used in a guided weapons system. The various methods used to investigate the failure mechanisms are discussed. These include details of the mechanical and chemical decapsulation techniques used to selectively remove the epoxy encapsulant without damaging the plastic encapsulated devices mounted on the substrate. Several failure mechanisms were discovered. With one exception, an isolated transistor failure, these were all the result of differential thermal expansion problems involving either the flexible conformal coating used, or the epoxy encapsulant.
Electronic characterization of double-gate thin film transistors. ][NANCHEN and FANG C. Luo. Solid-St. Electron. 24, 257 (1981). A method of determining the electronic parameters, i.e. the free charge carrier density, the surface
barrier. A possibly simplest model is assumed which consists in dividing the surface region of the semiconductor into two regions: (a) space-charge region, and (b) neutral region. An "internal boundary condition" to be satisfied on the boundary of those two regions is formulated. The expressions describing the current of the carriers of both types are derived for the case of thick base.
The diffusion of silicon in germanium. J. RAISANEN, J. HIRVONEN and A. ANTTILA. Solid-St. Electron. 24, 333 (1981). The diffusion coefficients of silicon in germanium as a function of temperature have been measured for the first time. The measurements were performed for lightly doped ntype and p-type germanium; because of the very slight difference observed in diffusion between these cases, the values 2.9 eV for the activation energy and 0.24 cm2/s for the frequency factor can be considered to correspond to those of intrinsic germanium. The 3°Si tracer element was implanted into the germanium samples and was detected using the (P,7) resonance broadening method. The annealing temperatures ranged from 650 to 900°C. M O S threshold voltage monitoring. W. A. BOSENBERG. RCA Rev. 41, 563 (December 1980). The threshold voltage of an MOS transistor is an important parameter that affects the performance of integrated circuits. Threshold voltage depends on oxide thickness, channel doping, substrate bias, metal work function, and surface state density. The dc monitoring of the threshold voltage can be greatly improved by including the substrate bias effect in the measurement. The procedure used extrapolates (to a zero drain current) threshold voltage from the drain-current/gate-voltage square-law characteristics. A second least-square fit is used for the dependence of the extrapolated threshold voltage with substrate bias. The fitting parameter is the channel concentration. The procedure makes it possible to analyze the threshold voltage as a function of an effective surfacestate density. The values calculated from the experiments are invariable over a limited temperature range.
A physical interpretation of dispersive transport in disordered semiconductors. T. TIEDJE and A. ROSE. Solid-St. Commun. 37, 49 (1980). We propose a physical interpretation for the dispersive charge transport arising from a distribution of localized states in disordered semiconductors. The principal results of the statistical theory of Scher Montroll are derived from elementary physical arguments, based on the progressive thermalization of electrons in an experimental distribution of traps. The model can be adapted to an arbitrary distribution of traps and gives a quantitative expression for the transit time.
HYBRID
CIRCUITS
AND
MATERIALS
state density and the bulk trap state density, of the semiconductor in double-gate thin film transistors is described. The method is based on a comparison of the calculated field-effect conductance with the observed drain current of the device. The theory is formulated such that it applies even though the semiconductor is thin compared with the effective Debye lengths. An illustrative example of the method applied to a CdSe double-gate thin film transistor is given.
Progress in and technology of low-cost silver containing thickfilm conductors. BARRY E. TAYLOR,JOHN J. FELTEN and JOHN R. LARRY. IEEE Trans. Components, Hybrids, Manuf Technol. C H M T - 3 (4) 504 (December 1980). The development of low-cost silver-bearing conductors is outlined and the evolution of technology improvements to present day systems is described. Initially the deficiencies of early Pd/Ag conductors are reviewed, particularly solder leach resistance and degradation of soldered adhesion
World Abstracts on Microelectronics and Reliability
main problems in the development of planar MOS components are discussed. In the end, the various GaAs logic kinds are compared with regard to the attained parameters, to this end, a classification of the known logic circuits on silicon basis is made.
Low frequency excess noise in SOS M O S FET's. S. T. Hsu. RCA Rev. 41, 577 (December 1980). Noise in SOS fieldeffect transistors has been investigated in the 20 Hz to 1 M H z frequency range. The measurements were made with frequency, drain bias voltage, gate bias voltage, and temperature as parameters. The low-frequency excess noise source was identified as electron trap states in the thin silicon film. The electron trap states are located at 0.65 eV below the edge of the conduction band. The effective barrier height of the electron trap state was found to decrease with increasing drain bias voltage. The experimental results also indicate that in thin silicon films grown on sapphire substrates, the densities of hole trap states and generation recombination centers are very small compared to that of electron trap states.
Luminescence and lattice defects in Cu In S 2. G. MASSE, N. LAHLOU and C. BUTTI. J. Phys. Chem. Solids 42, 449 (1981). We have studied the cathodoluminescence of single crystals of Cu In S 2 obtained by iodine chemical transport. As grown crystals annealed in In, S, (In + S), or in vacuum, were used. Two types of spectrum were observed, one for n type crystals due to S vacancies, and the other for p type or compensated crystals, which is interpreted as donor-acceptor pair transitions (determined by Time Resolved Spectroscopy) between the S vacancy (donor ~ 90 meV) and the Cu vacancy (acceptor~45meV), and by the corresponding free-tobound transitions.
Semiconductor industry silicon: physical and thermodynamic properties. CARL L. YAWS, LARRY L. DICKENS, RALPH LUTWACK and GEORGE HSU. Solid-St. Technol. 87 (January 1981 ). Pertinent physical and thermodynamic properties are presented for silicon which has important and diverse uses in the semiconductor industry; in integrated circuits, in power devices, and in photoelectric solar cells. The data includes critical properties, vapor pressure, heat of vaporization, heat of sublimation, heat capacity, density, surface tension, viscosity, and thermal conductivity.
Diffusion theory of the steady-state flow of minority-carrier current through the Schottky barrier. STANISLAW SIKORSKt. Electron Technol. 12 (3) 13 (1979). The paper presents a generalized version of the Scharfetter theory of Schottky
8. T H I C K -
AND
THIN-FILM
COMPONENTS,
Failure analysis techniques applied to expoxy encapsulated thick-film hybrids. ALAN G. BROWN. Solid-St. Technol. 136 (February 1981). Failure analysis was performed on a number of defective thick-film voltage regulator modules widely used in a guided weapons system. The various methods used to investigate the failure mechanisms are discussed. These include details of the mechanical and chemical decapsulation techniques used to selectively remove the epoxy encapsulant without damaging the plastic encapsulated devices mounted on the substrate. Several failure mechanisms were discovered. With one exception, an isolated transistor failure, these were all the result of differential thermal expansion problems involving either the flexible conformal coating used, or the epoxy encapsulant.
Electronic characterization of double-gate thin film transistors. ][NANCHEN and FANG C. Luo. Solid-St. Electron. 24, 257 (1981). A method of determining the electronic parameters, i.e. the free charge carrier density, the surface
barrier. A possibly simplest model is assumed which consists in dividing the surface region of the semiconductor into two regions: (a) space-charge region, and (b) neutral region. An "internal boundary condition" to be satisfied on the boundary of those two regions is formulated. The expressions describing the current of the carriers of both types are derived for the case of thick base.
The diffusion of silicon in germanium. J. RAISANEN, J. HIRVONEN and A. ANTTILA. Solid-St. Electron. 24, 333 (1981). The diffusion coefficients of silicon in germanium as a function of temperature have been measured for the first time. The measurements were performed for lightly doped ntype and p-type germanium; because of the very slight difference observed in diffusion between these cases, the values 2.9 eV for the activation energy and 0.24 cm2/s for the frequency factor can be considered to correspond to those of intrinsic germanium. The 3°Si tracer element was implanted into the germanium samples and was detected using the (P,7) resonance broadening method. The annealing temperatures ranged from 650 to 900°C. M O S threshold voltage monitoring. W. A. BOSENBERG. RCA Rev. 41, 563 (December 1980). The threshold voltage of an MOS transistor is an important parameter that affects the performance of integrated circuits. Threshold voltage depends on oxide thickness, channel doping, substrate bias, metal work function, and surface state density. The dc monitoring of the threshold voltage can be greatly improved by including the substrate bias effect in the measurement. The procedure used extrapolates (to a zero drain current) threshold voltage from the drain-current/gate-voltage square-law characteristics. A second least-square fit is used for the dependence of the extrapolated threshold voltage with substrate bias. The fitting parameter is the channel concentration. The procedure makes it possible to analyze the threshold voltage as a function of an effective surfacestate density. The values calculated from the experiments are invariable over a limited temperature range.
A physical interpretation of dispersive transport in disordered semiconductors. T. TIEDJE and A. ROSE. Solid-St. Commun. 37, 49 (1980). We propose a physical interpretation for the dispersive charge transport arising from a distribution of localized states in disordered semiconductors. The principal results of the statistical theory of Scher Montroll are derived from elementary physical arguments, based on the progressive thermalization of electrons in an experimental distribution of traps. The model can be adapted to an arbitrary distribution of traps and gives a quantitative expression for the transit time.
HYBRID
CIRCUITS
AND
MATERIALS
state density and the bulk trap state density, of the semiconductor in double-gate thin film transistors is described. The method is based on a comparison of the calculated field-effect conductance with the observed drain current of the device. The theory is formulated such that it applies even though the semiconductor is thin compared with the effective Debye lengths. An illustrative example of the method applied to a CdSe double-gate thin film transistor is given.
Progress in and technology of low-cost silver containing thickfilm conductors. BARRY E. TAYLOR,JOHN J. FELTEN and JOHN R. LARRY. IEEE Trans. Components, Hybrids, Manuf Technol. C H M T - 3 (4) 504 (December 1980). The development of low-cost silver-bearing conductors is outlined and the evolution of technology improvements to present day systems is described. Initially the deficiencies of early Pd/Ag conductors are reviewed, particularly solder leach resistance and degradation of soldered adhesion