Epitaxial Quality of Thin Ag Films on GaAs(100) Surfaces Cleaned with Various WetEtching Techniques

摘要

Two theta scans and pole figure X-ray analyses have been used to examine thecrystal structure and orientation of Ag films deposited on GaAs(100) substrates cleaned by a variety of wet etches. Where epitaxy was observed, it was of the type Ag(110)GaAs(100). The H3PO4/HCl sequential etch yielded the film with the highest degree of preferred orientation, with the H2SO4/HCl, NH4OH, and HF etches producing films of decreasing quality in the order named. The epitaxial quality is thought to scale with elemental As concentration on the GaAs(100) surface, and have an inverse relationship to the amount of surface oxides present before deposition.