Enhancement-Mode Buried-Channel $\hbox{In}_{0.7} \hbox{Ga}_{0.3}\hbox{As/In}_{0.52}\hbox{Al}_{0.48}\hbox{As}$ MOSFETs With High- $\kappa$ Gate Dielectrics

The operation of long- and short-channel enhancement-mode $\hbox{In}_{0.7} \hbox{Ga}_{0.3}\hbox{As}$-channel MOSFETs with high-$\kappa$ gate dielectrics are demonstrated for the first time. The devices utilize an undoped buried-channel design. For a gate length of 5 $\mu\hbox{m}$, the long-channel devices have $V_{t} = + \hbox{0.25}\ \hbox{V}$, a subthreshold slope of 150 mV/dec, an equivalent oxide thickness of 4.4 $+/-$ 0.3 nm, and a peak effective mobility of 1100 $\hbox{cm}^{2}/\hbox{V} \cdot \hbox{s}$. For a gate length of 260 nm, the short-channel devices have $V_{t} = + \hbox{0.5}\ \hbox{V}$ and a subthreshold slope of 200 mV/dec. Compared with Schottky-gated high-electron-mobility transistor devices, both long- and short-channel MOSFETs have two to four orders of magnitude lower gate leakage.