Growth and characterization of highly tensile-strained Ge on In xGa1-xAs virtual substrate by solid source molecular beam epitaxy

Abstract

Tensile-strained Ge is a promising material for Si-based optoelectronic integrated circuits and next-generation high-performance multijunction solar cells. We have grown highly tensile-strained Ge films on strain-relaxed In xGa1-xAs virtual substrates using solid-source molecular beam epitaxy. The tensile strain in a Ge film is controlled over a wide range from 0.40 to 1.55% by changing the In mole fraction in InxGa 1-xAs buffer layers. The 1.55% tensile strain achieved is much higher than previously reported values. These results demonstrate the usefulness of the InxGa1-xAs buffer method for investigating the properties of tensile-strained Ge. © 2009 The Japan Society of Applied Physics.