Superior reliability of high mobility (Si)Ge channel pMOSFETs

Abstract

• (Si)Ge channel pMOS technology offers remarkably reduced Negative Bias Temperature Instability (NBTI) at ultra-thin EOT. • We ascribe this property to a reduced interaction of channel holes with dielectric defects thanks to energy decoupling. • The reduced NBTI projects to a dramatic reduction of the time-dependent variability in nanoscale devices. • Other device degradation mechanisms are shown not to constitute showstoppers. With a significantly reduced Negative Bias Temperature Instability (NBTI), SiGe channel pMOSFETs promise to virtually eliminate this reliability issue for ultra-thin EOT devices. The intrinsically superior NBTI robustness of the MOS system consisting of a Ge-based channel and of a SiO 2 /HfO 2 dielectric stack is understood in terms of a favorable energy decoupling between the SiGe channel and the gate dielectric defects. Thanks to this effect, a significantly reduced time-dependent variability of nanoscale devices is also observed. Other reliability mechanisms such as low-frequency noise, channel hot carriers, and time-dependent dielectric breakdown are shown not to be showstoppers.