High-Mobility Strained SiGe-on-Insulator pMOSFETs With Ge-Rich Surface Channels Fabricated by Local Condensation Technique

摘要

A new approach to form strained SiGe-on-insuIator (SGOI) channel transistors, allowing fabrication of MOSFETs with very high Ge fraction in selected areas on a silicon-on-insu-lator substrate, is demonstrated. This method consists of epitaxial growth of an SiGe layer with a low Ge fraction and local oxidation processes. An obtained SGOI pMOSFET with a Ge fraction of 0.93 exhibits up to a tenfold enhancement in mobility. It is also found that MOSFETs having strained SGOI channels with thicknesses of less than 5 nm exhibit hole-mobility enhancement factors of over two. These results indicate that the local SGOI channels fabricated by the proposed technique are promising for implementation of high-mobility SiGe or Ge-channel MOSFETs in system-on-chip (SoC) devices.