Effects of $\hbox{Al}_{2}\hbox{O}_{3}$ Dielectric Cap and Nitridation on Device Performance, Scalability, and Reliability for Advanced High- $\kappa$ /Metal Gate pMOSFET Applications

摘要: A pFET threshold-voltage (Vt) reduction of about 200 mV is demonstrated by inserting a thin Al2O3 layer between the high-k dielectric and TiN gate without noticeable degradation other electrical properties. HfSiOpropcapped with 9 Aring Al2O3obtains low long-channel Vt -0.37 V (the lowest among those gate), high mobility 59 cm2 /V ldr s at 0.8 MV/cm (92% universal value), negligible equivalent- oxide-thickness (EOT) increase 0.1 (compared to uncapped reference), instability 4.8 7 MV/cm. It also passes ten-year negative-bias-temperature-instability (NBTI) lifetime specification overdrive -0.7 V. This indicates that caps are beneficial applications. In contrast, nitrogen incorporation in Al2O3-capped HfSiOprop not favorable because it increases 50-140 mV, degrades 10%-22%, EOT 0.5-0.8 5-13 reduces NBTI four five orders magnitude. Compared postcap nitridation, nitridation results more severe these properties incorporating closer Si/SiO2 interface.