Physical and Electrical Properties of Polycrystalline Si1 − xGex Deposited Using Single-Wafer-Type Low Pressure CVD

Abstract

Polycrystalline (poly) films have been suggested as a promising alternative to the currently employed poly silicon gate electrode for complementary metal oxide semiconductor field effect transistor technology due to lower resistivity, less boron penetration, and less gate depletion effect than that of poly Si gates. We investigated the deposition characteristics and physical properties of poly films using and as deposition source gases in single-wafer-type low pressure chemical vapor deposition (LPCVD) system and the electrical properties of MOS capacitors with the poly gate stack. Deposition rate as well as Ge content of poly films shows the large increase with the addition of a small fraction of while, above critical flux, it is slightly changed. In addition, the Ge content in poly films decreased with an increase in deposition temperature. The flatband voltage of the poly gate stack decreased by 0.3 V and gate depletion effect of poly gate stack was reduced by 18% as compared to that of the poly Si gate stack. In addition, the charge to breakdown of the poly gate stack was higher than that of poly Si gate stack. © 2003 The Electrochemical Society. All rights reserved.