Effect of high temperature deposition on the diffusion of nickel in amorphous silicon thin films

Abstract

The diffusion of nickel into amorphous Si (a-Si) thin films and the growth of different nickel silicides is reported. a-Si and Ni films were deposited on Borosilicate Glass substrates and annealed in vacuum at temperatures from 200 to 500°C. The average grain size of the films increases from 150 nm to 360 nm with deposition temperature. Cross-sectional scanning electron microscopy and energy dispersive x-ray spectroscopy have been used in conjunction to reveal the process of diffusion. It is inferred from x-ray diffraction and Raman spectroscopy analysis on these stacks that Ni3Si is formed at 200°C, NiSi at 300°C and NiSi2 at 400°C. This study reveals that Ni-Si bilayer films deposited at an elevated temperature and subsequently annealed at the deposition temperature formed monophase Ni silicides. © 2014 The Korean Institute of Metals and Materials and Springer Science+Business Media Dordrecht.