Interdiffusion of the p-InP with Au−Zn,Ti/Au,Pd/Au,Ti/Pd/Au at interface and their electrical properties

In this report, the interdiffusion between the p-InP with Au−Zn, Ti/Au, Pd/Au and Ti/Pd/Au at interface have been investigated by Auger electron spectroscopy and electron spectroscopy for chemical analysis. The surface morphology for the heat treatment are observed with scanning electron microscopy. It is found that the indiffusion of Au is easier than that of Pd and Ti and the outdiffusion of In is easier than that of P. The combination state of In and Au is formed during the heat treatment of p-InP/Au−Zn. The effects of the alloying temperature and time on the specific contacts resistance of p-InP/Au−Zn system are studied. The low specific contact resistance,ρ _e=2.4−2.7×10⁻⁴Ω-cm², is obtained when alloying at 450°C for 2 min or at 350°C for 30 min. These results indicate that the specific contact resistance strongly depend on the “interdiffusion degree”. The Zn in Au−Zn alloy distributes onto the most surface layer of p-InP/Au−Zn system during evaporation process and heat treatment. It may be one of the reasons for the higher specific contacts resistance.