Epitaxial Silicon Thin Films by Low Temperature Aluminum Induced Crystallization of Amorphous Silicon

Abstract

Epitaxial silicon thin film growth has been achieved on crystalline silicon substrates using aluminum induced crystallization of amorphous silicon. The phenomenon of layer inversion has been utilized in this process. Silicon wafers <100> were used as the starting crystalline structure for the grown films. After the wafer is cleaned a thin layer of aluminum (300 nm) was deposited by sputtering. This deposition was followed by 300 nm film of amorphous silicon deposited using plasma enhanced chemical vapor deposition method. After annealing the samples for 40 minutes at 525 °C, a continuous film of silicon was formed on the silicon substrate. X-ray diffraction spectrum indicated that this film has the same orientation as that of the substrate. Scanning electron microscopy cross section images showed indistinguishable interface between the substrate and the crystallized film. Cross sectional transmission electron microscopy studies of the crystallized structure showed epitaxial nature of the films.