Strained Silicon Layer in CMOS Technology

Abstract

Semiconductor industry is currently facing with the fact that conventional submicron CMOS technology is approaching the end of their capabilities, at least when it comes to scaling the dimensions of the components. Therefore, much attention is paid to device technology that use new technological structures and new channel materials. Modern technological processes, which mainly include ultra high vacuum chemical vapor deposition, molecular beam epitaxy and metal-organic molecular vapor deposition, enable the obtaining of ultrathin, crystallographically almost perfect, strained layers of high purity. In this review paper we analyze the role that such layers have in modern CMOS technologies. It’s given an overview of the characteristics of both strain techniques, global and local, with special emphasis on performance of NMOS biaxial strain and PMOS uniaxial strain. Due to the improved transport properties of strained layers, especially high mobility of charge carriers, the emphasis is on mechanisms to increase the charge mobility of strained silicon and germanium, in light of recent developments in CMOS technology.

Keywords

• Strained silicon layers
• uniaxial strain
• biaxial strain
• CMOS technology