A Detailed Study on Zero-Bias Irradiation Responses of $\hbox {La}_{\text{2}}\hbox {O}_{\text{3}}$ MOS Capacitors

$\hbox {La}_{2}\hbox {O}_{3}$
as a possible dielectric layer for a capacitor in MOS-based radiation sensors has been investigated under gamma irradiation doses up to 64 Gray. Capacitance–Voltage (C–V) and Conductance–Voltage (
$\hbox {G}/\omega \hbox{-V}$
) characteristics including the series resistance (
${\hbox {R}_{\rm s}}$
) of the device have been studied. The
$\hbox {La}_{2}\hbox {O}_{3}$
thin-film crystal structures, phase identification, and the elemental compositions of the films were investigated by X-ray diffractometer and energy-dispersive X-ray spectroscopies. The density of the interface states (
${\hbox {D}_{\rm it}}$
) and fading characteristics were calculated following a series correlations to C–V and
$\hbox {G}/\omega \hbox{-V}$
measurements. A desired linear flat band voltage shift-dose relation was obtained using the capacitance measurements. We observed that
${\hbox {R}_{\rm s}}$
barely decreases as irradiation dose increases, which has a crucial effects mainly on conductance of the device characteristics.
${\hbox {D}_{\rm it}}$
features were improved with irradiation doses but still in the order of
${10^{10}}\ \hbox{eV}^{ - 1}\ \hbox{cm}^{-2}$
. This did not cause any significant device degradation through its operation. Finally, the fading values of the devices with
$\hbox {La}_{2}\hbox {O}_{3}$
layers were found to be close to that of conventional
$\hbox {SiO}_{2}$
layers. The outcomes suggest that
$\hbox {La}_{2}\hbox {O}_{3}$
may be a promising future gate dielectric material candidate for radiation sensors in given radiation dose range.