Scaled Gate Stacks for Sub-20-nm CMOS Logic Applications Through Integration of Thermal IL and ALD HfOx

The impact of gate insulator processes to achieve deeply scaled interlayer (IL)/high-k (HK) bilayer stacks for sub-20-nm CMOS on negative-bias temperature instability and positive-bias temperature instability is studied. IL scaling is done by novel low-thermal-budget rapid-thermal-process-based ultrathin IL and monolayer IL. Innovative IL top surface treatment enables integration of IL and atomic-layer-deposition-based hafnium oxide HK without vacuum break. Fully integrated stacks show scaling of equivalent oxide thickness down to ~6Å, with excellent gate leakage, mobility, and world-class BTI. The mechanism responsible for improved BTI is discussed.