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Noise in silicon and FET's at high electric fields
World Abstracts on Microelectronics and Reliability and L. A. K. WATT. Solid-St. Electron. 20, (1) 61 (1977). A computer model has been developed that simulates charge transport of carriers in a surface channel chargecoupled device. This model is based on the charge continuity and current transport equations with a time dependent surface field. The device structure of the model includes a source diffusion an input gate and transfer gate. The present model is the first real simulation of the input scheme of the surface-channel CCDs. The scooping and spilling techniques associated with the charge injection process are simulated by the input diffusion which is included in the model. As an application to a CCD practical problem the present model has been used to study the linearity of the electrical charge injection into surface channel charge-coupled devices. The generated harmonic components of a sinusoidal input are calculated using the transfer characteristics of the input stage obtained from the computer simulation. Using this model the spatial variations of the selfinduced fringing field and total currents under the storage and transfer gates were computed. The charge transfer mechanisms for short-gate (L _< 8/lm) CCDs was investigated. It was found that for short gates the charge transfer efficiency is governed mainly by the fringing field and selfinduced current mechanisms. The results of this study help to clarify the mechanism by which the signal-charge level and gate length affect the charge transfer efficiency.
Theory and experiment for silicon Schottky barrier diodes at high current density. J. M. WILKINSON, L D. WILCOCK and M. E. BRINSON. Solid-St. Electron. 20, (1) 45 (1977). Metal-silicon Schottky barrier diodes exhibit n values which theoretically vary as a function of doping and applied voltage. The expected variation depends on which theoretical model is used to describe the current transport. Titanium n-type silicon barriers were prepared. At a doping level of 3 x 1015 cm -3 the barrier height and n-value measured at 100mV were 0.485 _+ 0.005 V and 1.02 _+ 0.01 whereas for a doping level of 2 × 10Xgcm-3 the corresponding values were 0.500 _+ 0.005 V and 1.18 _+ 0.05. The experimental variation of the diode n value as a function of semiconductor band bending showed good agreement with the thermionic-diffusion model of Crowell and Beguwala: n values increased rapidly as the band bending fl---, 2, and n values were highest at a given fl for diodes with the lowest doping concentration. Similar results were obtained by measurements on magnesium and aluminium barriers on n-type silicon. An analysis of the results has shown that the variation of the diode saturation current Is follows the predictions of the thermionic-diffusion theory, although th6re were some anomalies at high current densities. The anomalies did not result from variation of the width of the undepleted region of the epitaxial silicon layer or from diode self-heating effects. Noise in silicon and FET's at high electric fields. KEIJI TAKAGI and KATSUYAMATSUblOTO. Solid-St. Electron. 20, (1) 1 (1977). The noise temperature of n-type silicon was measured on an epitaxial layer up to a field strength of 10KV/cm from 1 to 20MHz at 77°K. The result was applied to obtain an approximate form for the drain noise of an FET in the high electric field. We found that the noise increases in proportion to the product of the drain current and voltage in high electric fields. The noise of the FET was also measured and the experimental data show reasonable agreement with the theoretical expressions. Tunneling of electrons from Si into thermally grown SiO2. Z. A. WEINBERG. Solid-St. Electron. 20, (1) 11 (1977). Accurate measurements of electron tunneling at the Si-SiO 2
119
interface were performed using the decay of surface potential following charging of the exposed oxide surface by positive corona ions. The surface potential was measured by an automated Kelvin-probe arrangement. Comparison of results for various substrate dopings, crystallographic orientations and oxide film thicknesses is presented. A model for tunneling based on electrons being confined within the lowest subband at the Si-SiO2 interface is also discussed and compared to the Fowler-Nordheim expression.
The dielectric constant associated with direct interband transitions in germanium. B. G. MARTIN and R. F. WALLIS. Solid St. Commun. 21, p. 385 (1977). An expression for the complex dielectric constant associated with direct interband transitions in germanium has been obtained using a simple model. The model consists of four damped oscillators, and a fit to experimental results for the complex dielectric constant is made to obtain the model parameters, i.e. the oscillator frequencies and damping constants. The results show good agreement with experimental data over a broad range of frequencies. A model for doped-oxide-source diffusion with a chemical reaction at the silicon-silicon dioxide interface. UTPAL KR. CHAKRABARTI.Solid-St. Electron. 20, p. 111 (1977). A mathematical model for doped-oxide-source diffusion is proposed. In this model the concept of segregation of impurity at the silicon-silicon dioxide is used and also a constant of "rate limitation" is introduced through a chemical reaction at the interface. MIS capacitor with traps in semiconductor. A. JAKUBOWSKI and P. JAGODZlNSKL Electron. Technol., Warsaw 9, (1) 31 (1976). A simple model for MIS capacitor with single-level traps in semiconductor region is presented based on depletion approximation. Characteristics of surface spacecharge region and capacitance-voltage characteristics of the capacitor are determined at low and high frequencies.
A review of some charge transport properties of silicon. C. JACOBIN1, C. CANALI, G. OTTAVIANI and A. ALBERIGI QUARANTA. Solid-St. Electron. 20, p. 77 (1977). This paper reviews the present knowledge of charge transport properties in silicon, with special emphasis on their application in the design of solid-state devices. Therefore, most attention is devoted to experimental findings in the temperature range around 300 K and to high-field properties. Phenomenological expressions are given, when possible, for the most important transport quantities as functions of temperature, field or impurity concentration. The discussion is limited to bulk properties, with only a few comments on surface transport. Measurement of minority carrier lifetime profiles in silicon. G. SCHWAB, H. BERNT and H. REICHI. Solid-St. Electron. 20, p. 91 (1977). The influence of finite surface recombination velocity on the measurement of minority carrier lifetime has been studied. The method is based on measuring the phase shift between the a.c.-photocurrent of a Schottky contact and the incident light. The limit of spatial resolution has been shown by theoretical calculations to be about one diffusion length. Lifetime profiles have been measured by the use of a mercury capillary contact. Theoretical study of X-ray photoelecton spectrum of germanium valence electrons. V. V. NEMOSCHKALENKO,V. G. ALESHIN and Yu. N. KICHERENKO. Solid St. Commun. 20, p. 1155 (1976). The density of states and X-ray photoelectron spectra of germanium valence electrons have been calculated. It is shown that to describe the shape of the photoelectron energy distribution curve of the greatest importance is precise allowance for the particularities of energy
Theory and experiment for silicon Schottky barrier diodes at high current density. J. M. WILKINSON, L D. WILCOCK and M. E. BRINSON. Solid-St. Electron. 20, (1) 45 (1977). Metal-silicon Schottky barrier diodes exhibit n values which theoretically vary as a function of doping and applied voltage. The expected variation depends on which theoretical model is used to describe the current transport. Titanium n-type silicon barriers were prepared. At a doping level of 3 x 1015 cm -3 the barrier height and n-value measured at 100mV were 0.485 _+ 0.005 V and 1.02 _+ 0.01 whereas for a doping level of 2 × 10Xgcm-3 the corresponding values were 0.500 _+ 0.005 V and 1.18 _+ 0.05. The experimental variation of the diode n value as a function of semiconductor band bending showed good agreement with the thermionic-diffusion model of Crowell and Beguwala: n values increased rapidly as the band bending fl---, 2, and n values were highest at a given fl for diodes with the lowest doping concentration. Similar results were obtained by measurements on magnesium and aluminium barriers on n-type silicon. An analysis of the results has shown that the variation of the diode saturation current Is follows the predictions of the thermionic-diffusion theory, although th6re were some anomalies at high current densities. The anomalies did not result from variation of the width of the undepleted region of the epitaxial silicon layer or from diode self-heating effects. Noise in silicon and FET's at high electric fields. KEIJI TAKAGI and KATSUYAMATSUblOTO. Solid-St. Electron. 20, (1) 1 (1977). The noise temperature of n-type silicon was measured on an epitaxial layer up to a field strength of 10KV/cm from 1 to 20MHz at 77°K. The result was applied to obtain an approximate form for the drain noise of an FET in the high electric field. We found that the noise increases in proportion to the product of the drain current and voltage in high electric fields. The noise of the FET was also measured and the experimental data show reasonable agreement with the theoretical expressions. Tunneling of electrons from Si into thermally grown SiO2. Z. A. WEINBERG. Solid-St. Electron. 20, (1) 11 (1977). Accurate measurements of electron tunneling at the Si-SiO 2
119
interface were performed using the decay of surface potential following charging of the exposed oxide surface by positive corona ions. The surface potential was measured by an automated Kelvin-probe arrangement. Comparison of results for various substrate dopings, crystallographic orientations and oxide film thicknesses is presented. A model for tunneling based on electrons being confined within the lowest subband at the Si-SiO2 interface is also discussed and compared to the Fowler-Nordheim expression.
The dielectric constant associated with direct interband transitions in germanium. B. G. MARTIN and R. F. WALLIS. Solid St. Commun. 21, p. 385 (1977). An expression for the complex dielectric constant associated with direct interband transitions in germanium has been obtained using a simple model. The model consists of four damped oscillators, and a fit to experimental results for the complex dielectric constant is made to obtain the model parameters, i.e. the oscillator frequencies and damping constants. The results show good agreement with experimental data over a broad range of frequencies. A model for doped-oxide-source diffusion with a chemical reaction at the silicon-silicon dioxide interface. UTPAL KR. CHAKRABARTI.Solid-St. Electron. 20, p. 111 (1977). A mathematical model for doped-oxide-source diffusion is proposed. In this model the concept of segregation of impurity at the silicon-silicon dioxide is used and also a constant of "rate limitation" is introduced through a chemical reaction at the interface. MIS capacitor with traps in semiconductor. A. JAKUBOWSKI and P. JAGODZlNSKL Electron. Technol., Warsaw 9, (1) 31 (1976). A simple model for MIS capacitor with single-level traps in semiconductor region is presented based on depletion approximation. Characteristics of surface spacecharge region and capacitance-voltage characteristics of the capacitor are determined at low and high frequencies.
A review of some charge transport properties of silicon. C. JACOBIN1, C. CANALI, G. OTTAVIANI and A. ALBERIGI QUARANTA. Solid-St. Electron. 20, p. 77 (1977). This paper reviews the present knowledge of charge transport properties in silicon, with special emphasis on their application in the design of solid-state devices. Therefore, most attention is devoted to experimental findings in the temperature range around 300 K and to high-field properties. Phenomenological expressions are given, when possible, for the most important transport quantities as functions of temperature, field or impurity concentration. The discussion is limited to bulk properties, with only a few comments on surface transport. Measurement of minority carrier lifetime profiles in silicon. G. SCHWAB, H. BERNT and H. REICHI. Solid-St. Electron. 20, p. 91 (1977). The influence of finite surface recombination velocity on the measurement of minority carrier lifetime has been studied. The method is based on measuring the phase shift between the a.c.-photocurrent of a Schottky contact and the incident light. The limit of spatial resolution has been shown by theoretical calculations to be about one diffusion length. Lifetime profiles have been measured by the use of a mercury capillary contact. Theoretical study of X-ray photoelecton spectrum of germanium valence electrons. V. V. NEMOSCHKALENKO,V. G. ALESHIN and Yu. N. KICHERENKO. Solid St. Commun. 20, p. 1155 (1976). The density of states and X-ray photoelectron spectra of germanium valence electrons have been calculated. It is shown that to describe the shape of the photoelectron energy distribution curve of the greatest importance is precise allowance for the particularities of energy