Single metal/single dielectric gate stack realizing triple effective workfunction for embedded memory application

Abstract

We demonstrate midgap and band-edge effective workfunctions (EWFs) control with simple metal gate process scheme (single metal gate/single gate dielectric), using impurity-segregated NiSi2/SiON structure for embedded memory application. The application of midgap and band-edge EWF enables us to lower power consumption in SRAM and logic devices by 30% and 15% compared to poly-Si devices, respectively, due to reduced channel impurity concentration, suppressed gate depletion and high carrier mobility. These results show that NiSi2/SiON stack is one of the most promising candidates for future system on chip (SoC) devices with embedded memory.