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Protective thin film coatings by plasma polymerization
586
World Abstracts on Microelectronics and Reliability
from 0 to 50%, target compositions, substrate temperature of 300K 573K on minimum resistivity at satisfactory transmittance and on reproducibility are discussed. The correlation between the electrical and optical properties and the microstructure of the films is shown.
Spectroscopy of excitons bound to isoclectronic defect complexes in silicon. E. C. LIGHTOWLERSand G. DAVIES.Solid St. Commun. 53 (12) 1055 (1985). A review is given of the axial isoelectronic bound exciton centres of current interest in silicon. A simple model is presented for the energy level structures of the bound excitons in which the axial nature of the optical centres is represented by an internal uniaxial stress acting on the band extrema of perfect silicon. This description is shown to provide a useful parameterisation of uniaxial stress and Zeeman data and to account for the relative transition probabilities of the various energy states. Avalanche breakdown in narrow gap semiconductors in crossed fields. E. V. BOGDANOV, N. B. BRANDT, L. S. FLEYSHMANand V. L. Povov. Solid St. Commun. 53 (11) 947 (1985). The paper presents the results of experimental and theoretical investigations of interband breakdown in narrow gap Bi~ _~Sb~ and Hg~ _~Cd~Te semiconductors in crossed electric and magnetic fields. Both these alloys show an increase of breakdown electric field in sufficiently strong magnetic field. In the case of Hg~ ~.Cd~Te the breakdown field changes nonmonotonically with H. This is interpreted as being due to the transverse breakdown. Highly excited states of donor centres in silicon. Solid St. Commun. 54 (1) 57 (1985). We report the observation under appropriate conditions of odd-parity absorption lines in the spectra of two S-related centres in silicon, associated with very low binding energies. Most of these levels can be identified by extension of the effective mass calculations. One level near 0.43meV is attributed to 1 0 f ± - 1 0 h ± and the shallowest one (0.34meV) cannot be attributed presently with any certainty. Heavy doping effects on bandgaps, effective intrinsic carrier concentrations and carrier mobilifies and lifetimes. HERBERT S. BENNETT. Solid-St. Electron. 28 (1/2) 193 (1985). Conventional device physics in most computer models of transistors may not predict correctly the measured electrical performance for shallow, heavily doped transistors. This paper presents improved concepts for numerical simulations of solid-state devices with donor densities up to 3 x 102°cm 3 and junction depths as small as 1 #m. These improved concepts pertain to bandgap narrowing, effective intrinsic carrier concentrations and carrier mobilities and lifetimes. Energy-gap reduction in heavily doped silicon: causes and consequences. SOKRATEST. PANTELIDES,ANNABELLASELLONI and ROBERTOCAR. Solid-St. Electron. 28 (1/2) 17 (1985). The authors review briefly the existing theoretical treatments of the various effects that contribute to the reduction of the energy gap in heavily doped Si, namely electron-electron and electron-impurity interactions and the effect of disorder in the impurity distribution. They then turn to the longstanding question why energy-gap reductions extracted from three different types of experiments have persistently produced values with substantial discrepancies, making it impossible to compare with theoretical values. First, they demonstrate that a meaningful comparison between theory and experiment can indeed be made if theoretical calculations are carried out for actual quantities that experiments measure, e.g. luminescence spectra, as recently done by Selloni and Pantelides. Then, they demonstrate that, independent of any theoretical calculations, the optical absorption spectra are fully consistent with the luminescence spectra and that the discrepancies in the energy-gap
reductions extracted from the two sets of spectra are caused entirely by the curve-fitting procedures used in analyzing optical-absorption data. Finally, they show explicitly that, as already believed by many authors, energy-gap reductions extracted from electrical measurements on transistors do not correspond to true gap reductions. They identify two corrections that must be added to the values extracted from the electrical data in order to arrive at the true gap reductions and show that the resulting values arc in good overall agreement with luminescence and absorption data. They, therefore, demonstrate that the observed reduction in emitter injection efficiency in bipolar transistors is not strictly due to a gap reduction, as generally believed, but to three very different effects.
Gettering in processed silicon. D. K. SAI)ANA.Semiconductor Int. 362 (May 1985). Recent work demonstrates a direct correlation between improved electrical performance and yield of devices. Characterizing plasma phosphorus-doped oxides. J.~A HOUSKOVA, KIM-KHANH N. HO and MARJORIEK. BALAZS. Semiconductor Int. 236 (May 1985). Three compounds of phosphorus have been verified in plasma deposited phosphosilicate glass and borophosphosilicate glass films. Evidence shows the presence of a fourth phosphoruscontaining compound. Protective thin film coatings by plasma polymerization. R. K. SADHlR and H. E. SAUr~DERS.Semiconductor Int. 110 (March 1985). Plasma polymerization of thin coatings on semiconductor devices produces a dense, crosslinked film which is an effective moisture barrier. Determination of diffusion characteristics using two- and fourpoint probe measurements. ROGER BRENNAN and DAVID DICKEY. Solid St. Technol. 125 (December 1984). By the use of two- and four-point probe measurements, much can be learned about the characteristics of a doped silicon wafer. The two-point probe system (spreading resistance probe) will provide resistivity vs depth profiles while the four-point probe system will indicate the uniformity of the diffusion over the surface of the wafer. Both systems have the same equation as their basis. The development of each system from this equation is discussed. Applications and the strengths and weaknesses of each system are discussed. On experimental data of the TCR of TFRs and their relation to theoretical models of conduction mechanism. I. STORBECK and M. WOLF. Electrocomponent Sci. Technol. 11 255 (1985). Any theory of electrical conduction in TFRs encounters mainly two problems: (i) explanation of the dependence of R[] on properties of conducting component (volume fraction, grain size, resistivity), (ii) explanation of the temperature dependence of RU taking into account (i). In order to achieve this one has to fit some microscopic parameters to experimental R D- and TCR-values, and to check if they are reasonable or not. The aim of the following discussion is to show, that such a fitting by means of experimental TCR-values is not correct. This is due to the fact that TCR-behaviour, as is well known, is determined also by the dependence of resistivity on strain. But any theoretical model neglects strains, also those who are induced by thermal strains. By means of published experiments concerning the strain dependence of resistance, the magnitude is estimated by which the TCR-values have to be corrected for the described fit. Fabrication of damage free micropatterns in silicon. R. P GUPTA, P. R. DESHMUKH,W. S. KHOKLEand AMARJITSINGH. Microelectron. Reliab. 24 (4) 623 (1984). A simple technique is reported for engraving damage free micropatterns in silicon. A pattern is written in PMMA by electron-beam
World Abstracts on Microelectronics and Reliability
from 0 to 50%, target compositions, substrate temperature of 300K 573K on minimum resistivity at satisfactory transmittance and on reproducibility are discussed. The correlation between the electrical and optical properties and the microstructure of the films is shown.
Spectroscopy of excitons bound to isoclectronic defect complexes in silicon. E. C. LIGHTOWLERSand G. DAVIES.Solid St. Commun. 53 (12) 1055 (1985). A review is given of the axial isoelectronic bound exciton centres of current interest in silicon. A simple model is presented for the energy level structures of the bound excitons in which the axial nature of the optical centres is represented by an internal uniaxial stress acting on the band extrema of perfect silicon. This description is shown to provide a useful parameterisation of uniaxial stress and Zeeman data and to account for the relative transition probabilities of the various energy states. Avalanche breakdown in narrow gap semiconductors in crossed fields. E. V. BOGDANOV, N. B. BRANDT, L. S. FLEYSHMANand V. L. Povov. Solid St. Commun. 53 (11) 947 (1985). The paper presents the results of experimental and theoretical investigations of interband breakdown in narrow gap Bi~ _~Sb~ and Hg~ _~Cd~Te semiconductors in crossed electric and magnetic fields. Both these alloys show an increase of breakdown electric field in sufficiently strong magnetic field. In the case of Hg~ ~.Cd~Te the breakdown field changes nonmonotonically with H. This is interpreted as being due to the transverse breakdown. Highly excited states of donor centres in silicon. Solid St. Commun. 54 (1) 57 (1985). We report the observation under appropriate conditions of odd-parity absorption lines in the spectra of two S-related centres in silicon, associated with very low binding energies. Most of these levels can be identified by extension of the effective mass calculations. One level near 0.43meV is attributed to 1 0 f ± - 1 0 h ± and the shallowest one (0.34meV) cannot be attributed presently with any certainty. Heavy doping effects on bandgaps, effective intrinsic carrier concentrations and carrier mobilifies and lifetimes. HERBERT S. BENNETT. Solid-St. Electron. 28 (1/2) 193 (1985). Conventional device physics in most computer models of transistors may not predict correctly the measured electrical performance for shallow, heavily doped transistors. This paper presents improved concepts for numerical simulations of solid-state devices with donor densities up to 3 x 102°cm 3 and junction depths as small as 1 #m. These improved concepts pertain to bandgap narrowing, effective intrinsic carrier concentrations and carrier mobilities and lifetimes. Energy-gap reduction in heavily doped silicon: causes and consequences. SOKRATEST. PANTELIDES,ANNABELLASELLONI and ROBERTOCAR. Solid-St. Electron. 28 (1/2) 17 (1985). The authors review briefly the existing theoretical treatments of the various effects that contribute to the reduction of the energy gap in heavily doped Si, namely electron-electron and electron-impurity interactions and the effect of disorder in the impurity distribution. They then turn to the longstanding question why energy-gap reductions extracted from three different types of experiments have persistently produced values with substantial discrepancies, making it impossible to compare with theoretical values. First, they demonstrate that a meaningful comparison between theory and experiment can indeed be made if theoretical calculations are carried out for actual quantities that experiments measure, e.g. luminescence spectra, as recently done by Selloni and Pantelides. Then, they demonstrate that, independent of any theoretical calculations, the optical absorption spectra are fully consistent with the luminescence spectra and that the discrepancies in the energy-gap
reductions extracted from the two sets of spectra are caused entirely by the curve-fitting procedures used in analyzing optical-absorption data. Finally, they show explicitly that, as already believed by many authors, energy-gap reductions extracted from electrical measurements on transistors do not correspond to true gap reductions. They identify two corrections that must be added to the values extracted from the electrical data in order to arrive at the true gap reductions and show that the resulting values arc in good overall agreement with luminescence and absorption data. They, therefore, demonstrate that the observed reduction in emitter injection efficiency in bipolar transistors is not strictly due to a gap reduction, as generally believed, but to three very different effects.
Gettering in processed silicon. D. K. SAI)ANA.Semiconductor Int. 362 (May 1985). Recent work demonstrates a direct correlation between improved electrical performance and yield of devices. Characterizing plasma phosphorus-doped oxides. J.~A HOUSKOVA, KIM-KHANH N. HO and MARJORIEK. BALAZS. Semiconductor Int. 236 (May 1985). Three compounds of phosphorus have been verified in plasma deposited phosphosilicate glass and borophosphosilicate glass films. Evidence shows the presence of a fourth phosphoruscontaining compound. Protective thin film coatings by plasma polymerization. R. K. SADHlR and H. E. SAUr~DERS.Semiconductor Int. 110 (March 1985). Plasma polymerization of thin coatings on semiconductor devices produces a dense, crosslinked film which is an effective moisture barrier. Determination of diffusion characteristics using two- and fourpoint probe measurements. ROGER BRENNAN and DAVID DICKEY. Solid St. Technol. 125 (December 1984). By the use of two- and four-point probe measurements, much can be learned about the characteristics of a doped silicon wafer. The two-point probe system (spreading resistance probe) will provide resistivity vs depth profiles while the four-point probe system will indicate the uniformity of the diffusion over the surface of the wafer. Both systems have the same equation as their basis. The development of each system from this equation is discussed. Applications and the strengths and weaknesses of each system are discussed. On experimental data of the TCR of TFRs and their relation to theoretical models of conduction mechanism. I. STORBECK and M. WOLF. Electrocomponent Sci. Technol. 11 255 (1985). Any theory of electrical conduction in TFRs encounters mainly two problems: (i) explanation of the dependence of R[] on properties of conducting component (volume fraction, grain size, resistivity), (ii) explanation of the temperature dependence of RU taking into account (i). In order to achieve this one has to fit some microscopic parameters to experimental R D- and TCR-values, and to check if they are reasonable or not. The aim of the following discussion is to show, that such a fitting by means of experimental TCR-values is not correct. This is due to the fact that TCR-behaviour, as is well known, is determined also by the dependence of resistivity on strain. But any theoretical model neglects strains, also those who are induced by thermal strains. By means of published experiments concerning the strain dependence of resistance, the magnitude is estimated by which the TCR-values have to be corrected for the described fit. Fabrication of damage free micropatterns in silicon. R. P GUPTA, P. R. DESHMUKH,W. S. KHOKLEand AMARJITSINGH. Microelectron. Reliab. 24 (4) 623 (1984). A simple technique is reported for engraving damage free micropatterns in silicon. A pattern is written in PMMA by electron-beam