Growth of single crystalline germanium thin film on (100) silicon substrate

Abstract

Epitaxial growth of germanium thin films (GeTFs) on Si (111) and Si (100) substrates was investigated, and the prepared films were compared with the films grown on SiO2 substrates. Ge films were prepared in three steps. Initially, a Ge interlayer film with thickness of ∼ 10 nm was deposited on the substrate followed by annealing and recrystallization of the film. A Ge film with a thickness of 500 nm was then deposited. A single crystalline Ge film was grown on Si (100) whereas polycrystalline films were grown on the other substrates. The growth rate of the films depends on the type of the substrates used, which in turn determines the crystallinity of the films. Highly crystalline films were obtained with slow growth rates. The single crystalline epitaxial layer of GeTFs formed on Si (100) exhibited a lower threading dislocation density as compared with those grown on Si (111) and SiO2.