Dry thermal oxidation of a graded SiGe layer

A method for the dry thermal oxidation of a strained SiGe layer is proposed . By oxidation of a graded Si1-xGex layer, the effect of Ge pileup was sign ificantly reduced and the undesirable strain relaxation by defect formation is prohibited. After oxidation, the oxidized SiGe layer was homogenized by postannealing process, and thereby a SiO2/SiGe interface with good structu ral properties was obtained. During postannealing, the homogenization was s ignificantly enhanced by strain-induced diffusion, and it was clearly prove d by the uphill diffusion. This result can propose an alternative oxidation method of strained SiGe/Si heterostructures. (C) 2001 American Institute o f Physics.