Effects of fluorine incorporation on the negative-bias-temperature instability (NBTI) of P-channel MOSFETs

摘要

The impacts of fluorine incorporation on the characteristics of p{sup}+-poly-Si-gated PMOSFETs were measured before and after negative-bias-temperature-instability (NBTI) stress. Fluorine species was incorporated during S/D extension and/or deep S/D implantation using BF{sub}2{sup}+. A reduction in interface state density with higher F dosage is observed. Moreover, the NBTI resistance is also found to increase with increasing F incorporation, as long as the thermal budget is carefully controlled to prevent the occurrence of boron penetration phenomenon. These improvements can be ascribed to the replacement of the bonded H atoms by F ones at the Si-SiO{sub}2 interface. However, the threshold voltage as well as oxide thickness also varies with fluorine incorporation.