The high‐performance AuCr/SiO2/InSb metal‐oxide‐semiconductor capacitor was fabricated successfully using photoenhanced chemical vapor deposition. The 1200‐A˚‐thick SiO2layer was deposited on the InSb substrate at a temperature below 200 °C. Their electrical and structural properties were analyzed by capacitance‐voltage and Auger electron spectroscopy, respectively. The capacitance‐voltage results show that the optimal growth temperature of SiO2is 150 °C at which the flat‐band voltage of the capacitor is close to ideal and the slow interface state density is less than 5 × 1010cm−2. For SiO2deposited at a lower temperature, although the flat‐band voltage and interface state are poorer, the subsequent thermal annealing at 150 °C for 12 h improves both quantities to the level as the optimal condition. However, for SiO2deposited at a higher temperature (190 °C), the flat‐band voltage shifts to −4 V and the slow state density increases to 1.1 × 1011cm−2. It is found from the Auger depth profile that whatever the deposition temperature was a Si‐rich region followed by an oxygen‐rich region was formed at the SiO2/InSb interface. These observations are shown to be consistent with the electrical characteristics of the capacitor.