Sulfide pretreatment effects of liquid phase deposited TiO2 on AlGaAs and its application

The study explored titanium dioxide (TiO2) prepared by liquid phase deposition (LPD) deposited on (NH4)2Sx-treated aluminum gallium arsenide (AlGaAs), including the surface roughness by using atomic force microscopy (AFM) measurements and electrical properties. The leakage current density of MOS capacitor is approximately 6.83 × 10−7 A/cm2 at zero electric field for the sample without any pretreatment. The interface trap density (Dit) and the flat-band voltage shift (ΔVFB) are 4.46 × 1012 cm−2 eV−1 and 3.6 V, respectively. After the 10 min 5% (NH4)2Sx pretreatment, the leakage current density, Dit, and ΔVFB can be improved to 1.04 × 10−7 A/cm2 at zero electric field, 2.28 × 1012 cm−2 eV−1, and 2 V, respectively. The paper also demonstrates the application to the AlGaAs/InGaAs metal-oxide-semiconductor pseudomorphic high-electron-mobility transistor (MOS-PHEMT) using LPD-TiO2 after 10 min sulfide pretreatment.