Growth and characterization of Si1−xGex and Ge epilayers on (100) Si

Abstract

Two approaches to the growth of high‐quality epitaxial Ge epilayers on (100) Si have been investigated. The first consisted of compositional‐grading Si_1−xGe_x layers and the use of strained‐layer superlattices as dislocation filters. In general, this method produced unsatisfactory results, due to the difficulty in achieving good epitaxial growth in the Ge concentration interval 30%−70%. The second approach consisted of simply depositing pure Ge directly on (100) Si. Excellent epitaxial films with dislocation densities of less than 10⁷ cm⁻² and smooth morphology were obtained after optimization of the growth parameters. The initial growth temperature and post‐growth annealing were found to be critical in obtaining good epitaxial material.