Mechanism of formation of Ohmic contacts to ZnSe, ZnS, and mixed crystals ZnS<i>X</i>Se1−<i>X</i>

Abstract

The temperature range of Ohmic contact formation to ZnSe, ZnS0.5 Se0.5, and ZnS is presented. New experiments show contacts are formed by cooldown rather than by heatup and that contacts can be formed and removed reversibly by cyclic cooling and heating. This and other evidence suggest contact formation by liquid-phase epitaxy, as had been shown in group-IV and -III-V semiconductors, rather than diffusion. The role of wetting, which is necessary but not equivalent to contact formation, is discussed.