Performance improvement of La2O3/p-GaAs MOS capacitor by using Si pasivation layer

The RF sputtered La
₂
O
₃
/ p-GaAs MOS capacitors with and without Si interface passivation layer (IPL) have been fabricated and characterized. It has been observed that the presence of (La
₂
O
₃
)
_1-x
(SiO
₂
)
_x
at the interface improved the device characteristics in terms of oxide capacitance (~3.3 fF/μm
²
), frequency dispersion (~8%) and interface state density (~1.2×10
¹²
cm
^-2
eV
^-1
). The best device performance was obtained for Al/ La
₂
O
₃
/Si/p-GaAs samples annealed at 500
^o
C.