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Adaptability of the majority carrier concentration permanence assumption in modeling of the junctions
Автор: admin | 19 Апр 2010
УДК 621.382
Adaptability of the majority carrier concentration permanence assumption in modeling of the junctions
A. Baskys, Dr., V. Bleizgys
Выведены выражения, связывающие граничные концентрации основных носителей с падением напряжения на p-n переходе. Они получены на основе выражений Больцмана и условия квази-нейтральности. Предлагаемые выражения позволяют исследовать применимость предположения о постоянстве граничных концентраций основных носителей при моделировании p-n переходов. Представлены результаты анализа конкретных p-n переходов, применяя полученные выражения.
The equations, which relate the boundary concentrations of majority carriers with the voltage drop across the p-n junction, have been derived. The derivation is carried out on the basis of the Boltzmann relations and charge quasi-neutrality conditions. The obtained equations allow us to investigate the adaptability of the majority carrier concentration permanence assumption in modeling of the junctions. The concrete silicon p-n junctions have been analyzed using derived equations. Introduction The theory of the p-n junction, which is employed for the derivation of analytic models of the semiconductor devices used for electronic circuits simulation, is based on the assumption of the majority carrier concentration permanence. This assumption states that majority carrier hole and electron boundary concentrations at the edges of the depletion region are equal to impurity (acceptor and donor) concentrations and are independent on voltage drop across the junction. This assumption allows us to simplify the junction models, however, the permanence of the majority carrier boundary concentrations is often violated in the actual semiconductor devices [1–3]. Because of this, it is of interest to relate the boundary concentrations of the majority carriers with voltage drop across the junction and current of the junction. This allows us to estimate the validity regions of analytic models derived under the assumption of the majority carrier concentration permanence. Unfortunately, the classical theory of the junction does not suggest the equations, which relate the concentration of majority carriers with the voltage drop across the junction. The purpose of this work is to derive these equations and provide the analysis of concrete p-n junctions using these equations. The derivation is carried out on the basis of the commonly accepted Boltzmann relations and charge quasi-neutrality conditions that are acceptable at relatively high current density [1, 4].
Темы: Твердотельная электроника | Комментариев нет