Low equivalent oxide thickness of TiO2/GaAs MOS capacitor

High quality TiO2 film grown by MOCVD on p-type GaAs with (NH4)2S treatment was obtained. The characteristics of TiO2/GaAs MOS capacitor were further improved by post-metallization annealing treatment. The leakage current densities can reach 1.7 × 10−6 and 4.5 × 10−5 A/cm2 at ±2 V (2.7 MV/cm). The equivalent oxide thickness can reach 0.53 nm for the physical thickness of 7.5 nm. The dielectric constant is 52. The lowest interface state density is 4.7 × 1011 cm−2 eV−1 derived by the high-low frequency capacitance method.

► Ultra-thin MOCVD-TiO2 was grown on p-type GaAs with (NH4)2S treatment. ► TiO2/GaAs MOS capacitor can be further improved with post-metallization annealing. ► The leakage current densities reach 1.7 × 10−6 and 4.5 × 10−5 A/cm2 at ±2 V (2.7 MV/cm). ► The lowest interface state density is 4.7 × 1011 cm−2 eV−1. ► The equivalent oxide thickness reaches 0.53 nm.