High-k/metal gate system and related issues

Key factors on Hf-based high-k/metal gate (HK/MG) CMOS technology based on conventional gate first process for low operational power application are overviewed. WF tuning derived from ionic property of HK material, process cost, EOT scaling under defect free interface as well as low gate leakage current are issues to be overcome. The most important item is how to control the atomic distribution in the Hf-based HK/MG system, which is requisite for the importunate WF tuning and EOT scaling.