Minority-carrier injection in Pt—Si Schottky-barrier diodes at high current densities

This paper presents a study of minority-carrier injection in platinum-silicide Schottky-barrier diodes at room temperature under steady-state dc bias for current densities extending to 10⁵A /cm². The phenomenon is experimentally investigated by measuring the minority-carrier storage using a reverse-recovery technique and by measuring the conductivity-modulated J-V characteristics. The theoretical treatment is based on a one-dimensional numerical simulation of the equations governing steady-state dc carrier transport in the device, corrected for lateral voltage drop in the n⁺buried layer. Simulation results are in good agreement with the measured carrier storage as well as the J-V characteristics. The minority-carrier injection ratio is calculated to be about 0.3 percent at 10⁵A/cm². This degree of injection causes appreciable conductivity modulation and leads to stored charge densities on the order of 10^-5C/cm². For reverse switching currents on the order of 10⁴A/cm², the majority of excess carriers were observed to discharge during the first 2 ns of reverse-recovery while a secondary discharge of minority carriers, lasting a few additional nanoseconds, was observed.