Impacts of Uniaxial Compressive Strain on Dynamic Negative Bias Temperature Instability of p-Channel MOSFETs

摘要

Dynamic negative bias temperature instability (DNBTI) characteristics of p-metal oxide semiconductor field-effect transistors (p-MOSFETs) with compressive channel strain induced by a SiN-capping layer were investigated. Although the SiN-capping is effective in boosting the device drive current, it may concomitantly worsen DNBTI characteristics. This is ascribed to higher hydrogen content incorporated during SiN deposition as well as higher strain energy stored in the channel. A strong dependence on the ac stress frequency is also observed for the SiN-capped devices, which is ascribed to excess hydrogen species contained in the strained devices. Finally, our experimental results also suggest that the aggravated NBTI in the strained devices could be alleviated by high frequency operation.