Strain analysis in ultrathin SiGe-on-insulator layers formed from strained Si-on-insulator substrates by Ge-condensation process

Ultrathin strained SiGe-on-insulator (sSGOI) layers were fabricated by Ge condensation, in which Si1−xGex layers on strained Si-on-insulator (sSOI) substrates were oxidized, and their strain and defects were investigated. With increasing the Ge fraction x, the compressive strain in the SGOI layers was found to linearly increase up to ∼2%. The linear strain dependence on x was offset by the preexisting tensile strain in the sSOI substrate compared to that of conventional SGOI layers formed on unstrained SOI substrates. As a result, pseudomorphic sSGOI layers were obtained on the sSOI substrate up to higher x (∼0.75) than on a SOI substrate.