Reduction of local mechanical stress in a transistor using Si 3N4/SiOxNy, contact ESL

Abstract

We have investigated the influence of a contact etch-stop layer (ESL) on the local mechanical stress in a deep sub-micrometer complementary metal oxide semiconductor (CMOS) field-effect transistor using convergent-beam electron diffraction with nanoscale resolution. By introducing a thin buffer layer of SiOxNy underneath the Si3N4 contact ESL, we have shown that the compressive channel strain can be effectively mitigated, resulting in higher electron mobility and drive current in n-channel metal oxide semiconductor field-effect transistors, without undue impact on the electrical performance of p-channel transistors. Hence, the Si3N 4/SiOxNy film stack is a promising alternative for contact ESL to enable high-performance CMOS devices. © 2004 The Electrochemical Society. All rights reserved.