Interface Optimization and Modulation of Leakage Current Conduction Mechanism of Yb2O3/GaSb MOS Capacitors With (NH4)2S Solutions Passivation

In current work, the impact of ammonium sulfide (NH
₄
)
₂
S solution passivation with varied pH value on the Yb
₂
O
₃
/n-GaSb interface has been investigated comparatively. Compared with control samples, the neutral (NH
₄
)
₂
S solution passivation can effectively reduce oxides layer on GaSb surface and gate leakage via X-ray photoelectron spectroscopy(XPS) measurements and electrical characterization. High-low frequency capacitance method was used to evaluate interface-state density Dit, it was found that capping with Yb
₂
O
₃
can delaythe interface-state generation and the lowest Dit value of 5.18 × 10
¹²
cm
^-2
eV
^-1
for Yb
₂
O
₃
/GaSb capacitor with neutral (NH
₄
)
₂
S was achieved. Moreover, the possible leakage current conduction mechanisms for capacitors measured at room temperature and low temperature have also been discussed systematically.