Comparisons of Ag deposits on Ge and Si(111)

Abstract

Crystal growth and surface diffusion have been studied in the Ag Ge(111) system using ultra-high vacuum scanning electron microscopy (UHV-SEM) based techniques, biassed secondary electron imaging (b-SEI), micro-AES and RHEED. Ag was deposited through and past a mask of holes held close to the substrate at 20 < T d < 500°C. Under certain conditions, the Ag patches were observed to split into two regions corresponding to the √3 × √3R30° (hereafter √3) and a lower coverage (4 × 4) structure, each of which were easily observable using b-SEI. These patch widths were measured as a function of T d, and of annealing times at temperatures T a, and effective diffusion coefficients extracted. The coverage of the √3 Ag Ge(111) layer is close to 1 ML throughout the temperature range studied, unlike √3 Ag Si(111) , where it depends on deposition and annealing conditions.