The space charge capacitance of a p–n junction

Abstract

Starting from a general expression for the space charge capacitance derived elsewhere and the Moll assumption of constant quasi-Fermi levels, a representation of this capacitance in the form of a convergent series is presented. The first and most important term in this seriesis the point at which the electron and hole concentrations are equal and E ( 0 ) and M(zo) are the electric field and net doping concentration a t that point. This result is used t o derive a formula for the space charge capacitance of an abrupt asymmetric junction which is in better agreement with experiment than the Schottky-Shockley formula. Onpr&sente partant d'une formule gentkale pour la capacite de la chargc d'espace tire d'ailleurs e t de la hypothbe de Moll que les niveaux quasi-Fermi sont constants, une representation de cette capacit6 dans la forme d'une serie convergente. Le prcmier termc et le plus important dans cette series est C, = EE, ---pN(zo) -oh zo est le point oh les concentrations des 6lectrons et des trous sont &gales, et E(0) et M ( z 3 ) sont le champ Blectrique et la concentration dopante nette it ce point. On emploie ce resultat pour tirer une expression pour la capacit6 de la charge d'espace d'une jonction abrupte asymmetrique qui est en meillenr accord avec des experiences que la formule Schottky-Shockley. c = --kT p d Y f d Y ' dR 2 cosh2 Y m D J J " -Y P -YP

Space-charge capacitance of an abrupt p–n junction

“…Leonidou (1) and the results applied to a calculation of space charge capacitance by Parrott (2). A power series solution was found which was related to previous calculations by Kleinknecht (3) and Smith (4) but was more rigorous and complete.…”