N2O oxidation of strained-Si/relaxed-SiGe heterostructure grown by UHVCVD

Abstract

Oxidation of strained-Si/relaxed-SiGe heterostructure grown by UHVCVD method using a rapid thermal processing technique in N2O ambient is investigated. The electrical properties of the grown oxide have been characterized using a MOS structure. Hole confinement in the SiGe layer at low field is observed from the capacitance-voltage curve and this suggests that the strain in the initially strained Si epilayer is retained after oxidation. The experimental results are compared with simulation results obtained from a 1D Poisson solver. Dit and Qf/q values are estimated to be 3 × 1011 cm-2eV-1 and -1.2 × 1011 cm-2, respectively. These high values of Dit and negative Qf/q could possibly be due to Ge out diffusion and pile up at the SiO2/strained-Si interface. The oxide exhibits an excellent breakdown field of 15 MVcm-1. © 2001 Elsevier Science Ltd. All rights reserved.