Sub-10-nm Extremely Thin Body InGaAs-on-Insulator MOSFETs on Si Wafers With Ultrathin $hbox{Al}_{2}hbox{O}_{3}$ Buried Oxide Layers

摘要

We have demonstrated sub-10-nm extremely thin body (ETB) InGaAs-on-insulator (InGaAs-OI) $n$MOSFETs on Si wafers with $ hbox{Al}_{2}hbox{O}_{3}$ ultrathin buried oxide (UTBOX) layers fabricated by direct wafer bonding process. We have fabricated the ETB InGaAs-OI $n$MOSFETs with channel thicknesses of 9 and 3.5 nm. The 9-nm-thick ETB InGaAs-OI $n$ MOSFETs with a doping concentration $(N_{D})$ of $hbox{10}^{19} hbox{cm}^{-3}$ exhibit a peak electron mobility of 912 $hbox{cm}^{2}/hbox{V}cdothbox{s}$ and a mobility enhancement factor of 1.7 times against the Si $n$MOSFET at a surface carrier density $(N_{s})$ of $hbox{3} times hbox{10}^{12} hbox{cm}^{-2}$. In addition, it has been found that, owing to $hbox{Al}_{2}hbox{O}_{3}$ UTBOX layers, the double-gate operation improves the cutoff properties. As a result, the highest on-current to the lowest off-current $(I_{rm on}/I_{rm off})$ ratio of approximately $hbox{10}^{7}$ has been obtained in the 3.5-nm-thick ETB InGaAs-OI $n$MOSFETs. These results indicate that the high-mobility III–V $n$MOSFETs can be realized even in sub-10-nm-thick channels.