NEW SURFACE PASSIVATION METHOD FOR GAAS AND ITS EFFECT ON THE INITIAL GROWTH STAGE OF A HETEROEPITAXIAL ZNSE LAYER

A new surface passivation method for GaAs substrate utilizing HCl-pretreatment is studied and the results are compared with those for conventional acid-etched and (NH4)2Sx-pretreated substrates. The substrates are characterized by XPS and RHEED. It is shown that the HCl pretreatment is useful for suppressing the formation of oxide layers on the surface, as in the case of (NH4)2Sx pretreatment. It is also shown that when using HCl-pretreated substrates two-dimensional nucleation can be achieved in the very initial growth stage of ZnSe. These results indicate that HCl pretreatment is useful for the passivation of GaAs surface, resulting in high-quality epilayer growth.