Performance and interface characterization for contact etch stop layer-strained nMOSFET with HfO2 gate dielectrics under pulsed-IV measurement

In this paper, high-performance contact etching stop layer (CESL)-strained n-metal-oxide-semiconductor field effect transistor (nMOSFET) with HfO2 gate dielectrics has been successfully demonstrated. The effects of the CESL layer to the high- k without trapping behaviors are investigated by the pulse current-voltage (IV) technique for the first time. It is found that a roughly 55 and 60% increase of mobility and ION, respectively, can be achieved for the 300 nm CESL HfO2 nMOSFET using pulsed-IV measurement. Furthermore, a superior HfO2 Si interface for CESL devices is observed, demonstrated by an obvious interface state density reduction (6× 1011 - 9× 1010 cm-2).