Effects of Process and Gate Doping Species on Negative-Bias-Temperature Instability of p-Channel MOSFETs

The effects of poly-Si gate doping type and species as well as thermal treatments on negative-bias-temperature instability (NBTI) of p-channel metal-oxide-semiconductor field effect transistors (MOSFETs) were investigated. We found that devices with n⁺-poly-Si gate depict a smaller threshold voltage shift after bias-temperature stressing, compared to their p⁺-poly-Si-gated counterparts. By carefully controlling the thermal budget to suppress boron penetration, NBTI can be reduced by fluorine incorporation in p⁺-poly-Si-gated devices. Finally, NBTI is found to be aggravated in devices subjected to H₂ postmetalannealing, highlighting the important role of hydrogen bonds.