Diffusion capacitance of an epitaxial high barrier schottky diode

Abstract

A Schottky barrier diode is a majority carrier device when the barrier height is low. But, it injects minority carrier at forward bias from the Schottky contact into the semiconductor when the barrier height is high. Minority carrier charge is stored within the drift region of a high barrier Schottky diode due to this minority carrier injection at forward bias. The stored charge in the drift region gives rise to diffusion capacitance that should not be ignored for the high barrier Schottky diode. No literatures have yet been published on the diffusion capacitance of a high barrier Schottky diode. In this work, an analytical expression for diffusion capacitance of an epitaxial high barrier Schottky diode has been developed. The expression is valid for all levels of injection. The effect of different parameters on the diffusion capacitance has been studied. It has been found that the diffusion capacitance depend on the junction voltage, total current density, drift region length and effective surface recombination velocity. The diffusion capacitance depends strongly on the junction voltage, current density and drift region length.