Effective Surface Passivation by Novel $hbox{SiH}_{4}$ –$hbox{NH}_{3}$ Treatment and BTI Characteristics on Interface-Engineered High-Mobility $hbox{HfO}_{2}$ -Gated Ge pMOSFETs

摘要

A novel surface passivation technique using silicon nitride (SN) by $ hbox{SiH}_{4}$–$hbox{NH}_{3}$ treatment has been demonstrated on $hbox{HfO}_{2}$-gated Ge pMOSFETs. It is found that ultrathin SN passivation is more effective to suppress the Ge out diffusion than ultrathin Si passivation. Improved interface quality and device performance were achieved for the device with the SN passivation. Fluorine (F) incorporation by postgate treatment was also implemented to further enhance the performance. Furthermore, bias temperature instability (BTI) characteristics were systematically investigated on interface engineered (Si-, SN-, or $hbox{GeO}_{2}$-passivated) Ge pMOSFETs by both conventional dc $I$– $V$ and fast pulse measurement. The impact of $ hbox{HfO}_{2}$ thickness and postgate treatment processes (F incorporation) on BTI and device performance was also studied, and it is found that BTI and device performance can be improved by reducing the $hbox{HfO}_{2}$ thickness or incorporating F.