Growth and characterization of Si1−<i>x</i>Ge<i>x</i> 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 Si1−xGex 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.