Enabling Effective Work Function Tuning by RF-PVD Metal Oxide on High-k Gate Dielectric

RF-PVD was investigated as a metal oxide cap deposition process to tune the effective work function in a gate first flow for high-k metal gate stacks. Samples with an aluminum oxide cap layer showed a large flat band voltage shift at minimal equivalent oxide thickness increase by about 0.1 nm. It was confirmed that RF-PVD induced no additional charge damage. Extended RF-PVD process runs also promised a robust process for high-k metal gate device manufacturing.