Strain relaxation during solid-phase epitaxial crystallisation of GexSi1-x alloy layers with depth dependent Ge compositions

Abstract

Solid-phase epitaxial growth (SPEG) of amorphous GeSi alloy layers has been examined. It is shown that fully strained depth dependent GeSi alloy layers can be produced by multiple ion-implantation and SPEG for implant doses below critical values. For doses above these critical values strain relaxation is shown to occur during SPEG at a well defined depth, and to be correlated with a reduction in the SPEG velocity caused by roughening or faceting of the crystalline/amorphous interface. The velocity reduction is shown to be a reliable indicator of strain relaxation. Both the critical dose and the depth at which strain relaxation occurs are shown to be in excellent agreement with equilibrium critical thickness theory. Show more