Evaluation of Surface Zn Concentration in Zn Diffusion into InP

The surface Zn concentration of Zn diffusion in InP was evaluated with a simple model using statistical thermodynamics, assuming that the Zn atoms in the vapor phase are isolated atoms of monoatomic gas and that the interaction between the incorporated Zn atoms in InP is negligible. The results confirmed that the surface Zn concentration obtained from diffusion experiments is well described in terms of this model. Thus, this analysis strongly supports the fact that Zn atoms are incorporated in InP not only as singly ionized acceptors, but also as singly ionized donors.