(100)- and (110)-oriented nMOSFETs with highly scaled EOT in La-silicate/Si interface for multi-gate architecture

This paper reports on detailed comparison between (100)- and (110)-oriented nMOSFETs with direct contact of La-silicate/Si interface structure for expansion to multi-gate architecture including FinFETs, trigate FETs, and nanowire FETs. Scaled EOT of 0.73 nm for (110)-oriented nMOSFETs has been achieved as well as (100)-oriented nMOSFETs. Although the large interface state density originating from (110) orientation was observed, fairly nice interfacial property was obtained from (110)-oriented nMOSFETs at scaled EOT region. Moreover, larger interface state density in (110) orientation did not affect on V_th instability. It was found that V_th shift of nMOSFETs is mainly caused by bulk trapping of electron in La-silicate as well as Hf-based oxides.