Bias and thickness dependence of the infra-red PtSi/p-Si Schottky diode studied by internal photoemission

A series of p-type PtSi/Si infra-red Schottky diodes with different metal thicknesses was studied at about 80 K by internal photoemission as a function of reverse bias. The zero-bias barrier height of PtSi/p-Si is found to increase only marginally with metal thickness. The Schottky emission coefficient is interpreted by a simple model and it is found that the mean free path of the carrier in Si decreases with the increase in the acceptor density of the semiconductor. We attribute this mainly to scattering of the carriers by the ionized impurities, as these are the dominant scatterers at low temperatures for lightly and moderately doped Si.