Defect Passivation With Fluorine and Interface Engineering for Hf-Based High- k/Metal Gate Stack Device Reliability and Performance Enhancement

Using a fluorinated high-fc/metal gate stack combined with a stress relieved preoxide (SRPO) pretreatment before high-fc deposition, we show significant device reliability and performance improvements. This is a critical result since threshold voltage instability may be a fundamental problem, and performance degradation for high-fc is a concern. The novel fluorinated Ta_xC_y/HfZrO_x/SRPO gate stack device exceeds the positive-bias-temperature-instability and negative-bias-temperature-instability targets with sufficient margin and has electron mobility at 1 MV/cm comparable to the industrial high-quality polySi/SiON device on bulk silicon.