High-performance metal/SiO2/InSb capacitor fabricated by photoenhanced chemical vapor deposition

Abstract

The high performance AuCr/Si02/InSb metal-oxidesemiconductor capacitor was fabricated successfully using photo-enhanced chemical vapor deposition. The 1200 A thick Si02 layer was deposited on the InSb substrate at the 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 Si02 is 150 °C at which the fiat-band voltage of the capacitor is close to ideal and slow interface state density is less than 5 x 1O'° cm2. For Si02 deposited at lower temperature, although the flatband voltage and interface state are poorer, the subsequent thermal annealing at 150 °C for 12 hours improves both quantities to the level as the optimal condition. However, for Si02 deposited at higher temperature (190 °C), the flatband voltage shifts to -4 V and the slow state density increases to 1.1 x 1011 cm2. It is found from Auger depth profile that whatever the deposition temperature was a Si-rich region followed by an oxygen-rich region was formed at the 5i02/InSb interface. These observations are shown to be consistent with the electrical characteristics of the capacitor.