Theoretical study of the depletion-layer capacitance in abrupt p–n semiconductor junctions

Abstract

For evaluation of capacitance‐voltage measurements on an abrupt pn semiconductor junction with reverse‐biased depletion layer an approximation equation for the quantity Ue is presented, where Ue is the value at the intercept of the extrapolated plot C−2 to the applied voltage axis. The approximation formula is compared with an exact calculation. The maximum error in the approximate relationship for Ue is less than 3% in a wide range of impurity density and applied reverse voltage, therefore the discrepancy in the space‐charge layer capacitance Cs is less than 1.5%. Cs is given by the relationship, which follows from Shockley's theory, if (U + UD) is replaced by (U + Ue).