Gate dielectrics on strained-Si/SiGe heterolayers

Abstract

The purpose of this article is to report on the recent developments on the gate dielectric formation on strained-Si/SiGe heterolayers. In the first part, growth of a high quality strained-Si layer on a relaxed, linear or step-graded SiGe buffer layer and SiGe-free strained-Si on Silicon-on-Insulator (SSOI) is briefly reviewed. Characterization results of strained-Si films using atomic force microscopy (AFM), transmission electron microscopy (TEM) and Raman spectroscopy are then presented. In the second part, the processing issues of gate dielectric formation on strained-Si films are critically examined and the thermal oxidation of strained-Si layers are discussed. Low thermal budget processing, such as rapid thermal oxidation (RTO) and low temperature microwave plasma oxidation and nitridation of strained-Si layers are discussed in the third part. Microwave plasma deposition of various high-k gate dielectrics, such as ZrO2, Ta2O5, and TiO2 on strained-Si, their electrical properties and the current conduction mechanisms are also discussed. © 2004 Elsevier Ltd. All rights reserved.