Performance of polysilicon gate HfO/sub 2/ MOSFETs on [100] and [111] silicon substrates

Mobility dependence on Si substrate orientations was investigated for HfO/sub 2/ MOSFETs for the first time. High-temperature (600 (degree)C) forming gas (FG) annealing (HT-FGA) was applied on the devices on both [100] and [111] substrates to evaluate the mobility for optimal interfacial quality. Using HT-FGA, D/sub it/ of the [111] devices was reduced down below 1 * 10/sup 12/ cm/sup -2/V/sup -1/. Similar to SiO/sub 2/ devices, NMOS mobility of the [111] devices was lower than that of the [100] devices at higher effective fields, while it was reversed for PMOSFETs.