Characteristics of SiN/GaAs interface under exposure to high-temperature and high-humidity conditions measured by photoreflectance spectroscopy

Abstract

We investigated the changes in the electrical properties of a SiN/GaAs interface under high-temperature and high-humidity conditions, using photoreflectance (PR) spectroscopy and the electrical device characteristics. The PR spectra show the Franz-Keldysh oscillation (FKO); these spectra show that the period decreases after the sample is exposed to humidity. The electric field strength obtained from the FKO period indicates that the initial high electric field decreases with humidity exposure. Decomposed water molecules are supposed to diffuse into the SiN layer and react with the SiN/GaAs interface, causing a decrease in the interface states.