Calculation of the Capacitance-Voltage Characteristics of p+-InP/n-InP/n-InGaAsP Photodiodes

摘要

An analytic solution for the capacitance-voltage characteristics of p(+)-InP/n-InP/n-InGaAsP diodes has been obtained. The solution, which closely approximates that obtained using numerical methods, indicates that the dip followed by a peak generally observed in the effective carrier concentration profile as derived from experimental capacitance measurements is likely due to the properties of the n-n heterojunction rather than actual variations in the doping concentration. The availability of the analytic solution greatly facilitates the study of the effects of various parameters on these characteristics. The influence on grading and the collection of holes in the notch formed by the valence band discontinuity is also briefly considered.