Substitutional-Gate MOSFETs With Composite $( \hbox{In}_{0.53}\hbox{Ga}_{0.47}\hbox{As}/\hbox{InAs}/\hbox{In}_{0.53}\hbox{Ga}_{0.47}\hbox{As})$ Channels and Self-Aligned MBE Source–Drain Regrowth

We report enhancement-mode composite-channel
$(\hbox{In}_{0.53} \hbox{Ga}_{0.47}\hbox{As}/\hbox{InAs}/\hbox{In}_{0.53}\hbox{Ga}_{0.47}\hbox{As})$
MOSFETs fabricated using a substitutional-gate process, with
$\hbox{n}^{+}$
relaxed InAs source–drain regions formed by regrowth by molecular beam epitaxy. A device with 70-nm gate length and 2-nm
$\hbox{In}_{0.53}\hbox{Ga}_{0.47}\hbox{As}$
/3.5-nm InAs/3-nm
$\hbox{In}_{0.53}\hbox{Ga}_{0.47}\hbox{As}$
channel showed a peak transconductance of greater than 0.76
$\hbox{mS}/\mu\hbox{m}$
at
$V_{\rm ds} = \hbox{0.4}\ \hbox{V}$
and showed
$I_{d} = \hbox{0.5}\ \hbox{mA}/\mu\hbox{m}$
at
$V_{\rm ds} = \hbox{0.4}\ \hbox{V}$
and
$V_{\rm gs} - V_{\rm th} = \hbox{0.7}\ \hbox{V}$
. The subthreshold swing at
$V_{\rm ds} = \hbox{0.1}\ \hbox{V}$
was 130 mV/dec.