(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 Vth instability. It was found that Vth shift of nMOSFETs is mainly caused by bulk trapping of electron in La-silicate as well as Hf-based oxides.

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