Physical and Electrical Analysis of Post-$ \hbox{HfO}_{2}$ Fluorine Plasma Treatment for the Improvement of $\hbox{In}_{0.53}\hbox{Ga}_{0.47}\hbox{As}$ MOSFETs' Performance

Notable improvements in the
$\hbox{HfO}_{2}/\hbox{In}_{0.53} \hbox{Ga}_{0.47}\hbox{As}$
gate stack have been achieved by a post-
$\hbox{HfO}_{2}$
fluorine plasma treatment, including excellent interface quality of low equivalent oxide thickness
$\hbox{HfO}_{2}$
(1.4 nm) directly on
$\hbox{In}_{0.53}\hbox{Ga}_{0.47}\hbox{As}$
without using an interface passivation layer,
$\sim\!\!\hbox{5}\times$
reduction in interface trap density from
$\hbox{2.8} \times \hbox{10}^{12}$
to
$\hbox{4.9} \times \hbox{10}^{11}\ \hbox{cm}^{-2}\hbox{eV}^{-1}$
,
$\sim\!\!\hbox{10}\times$
reduced border traps from
$\hbox{1.6} \times \hbox{10}^{19}$
to
$\hbox{1.6} \times \hbox{10}^{18}\ \hbox{cm}^{-3}$
, and
$\sim$
40% less charge-trapping centers. As a result, improved electrical performances have been obtained. Frequency dispersion in capacitance–voltage characteristics has been reduced. Subthreshold swing has been improved from 127 to 109 mV/dec. Effective channel mobility has been enhanced from 826 to 1067
$\hbox{cm}^{2}/\hbox{Vs}$
. An improved drive current of 123 mA/mm at
$V_{d} = \hbox{2.5}\ \hbox{V}$
and
$V_{g} - V_{\rm th} = \hbox{2}\ \hbox{V}$
(5-
$\mu\hbox{m}$
channel length) has been also presented.