Strain as driving force for interface roughening of δ-doping layers

Abstract

The growth of smooth and abrupt heteroepitaxial semiconductor interfaces is limited by strain originating from the lattice mismatch of the different materials. Employing measurements of crystal truncation rods, we have performed an extensive study of the impact of intra-layer strain on structural properties of ultra-thin ( δ) doping layers. The use of molecular beam epitaxy and related methods, i.e., the use of surfactants and low growth temperatures with subsequent annealing (solid phase epitaxy) allows the preparation of Bi, Sb, Ge and Si 1− x C x δ layers with doping profiles of monolayer width and high peak layer concentration (>10%). We find a linear dependence of the interface roughness on the intra-layer strain.