Local vibrational mode bands of V–O–H complexes in silicon

Abstract

H2 molecules, which are introduced into moderately doped silicon crystals by high-temperature in-diffusion from H2 gas ambient followed by fast cooling to room temperature, are found to interact effectively with the defects induced by irradiation of the crystals with fast electrons. In Czochralski-grown silicon crystals, the interaction of the mobile H2 molecules with vacancy-oxygen defects (A centers) leads to the creation of V–O–H2 complexes. This complex gives rise to infrared (IR) absorption lines at 943.5, 2126.4, and 2151.5cm−1. Ab initio calculations showed that the most stable configuration of V–O–H2 consists of one oxygen and two hydrogen atoms sharing a vacancy site. It is suggested that the interaction of the V–O–H2 complexes with interstitial oxygen atoms results in the formation of V–O2–H2 complexes, which are responsible for the IR absorption line at 891.5cm−1.