Gate-first high-k/metal gate stack for advanced CMOS technology

Practical and manufacturable solutions for metal gate/dual high-k CMOS integration are presented. In order to overcome the difficulties of threshold voltage control of metal gate/high-k gate stack especially for gate-first integration, several material designs have been proposed so far. These include different metal gate materials and different high-k materials which are separately used in nMOS and pMOS transistors. These approaches sometimes bring about complicated CMOS integration scheme. In this paper, therefore, we will give simple metal gate/dual high-k CMOS fabrication processes with low threshold voltages which are suitable for scaled CMOS device manufacturing.