Direct evidence of polycrystalline silicon thin films formation during aluminum induced crystallization by in-situ heating TEM observation

Abstract

The formation behavior of polycrystalline silicon thin films during the aluminum induced crystallization (AIC) process was investigated by scanning transmission electron microscopy (STEM) and in-situ heating transmission electron microscopy (TEM) observations. The STEM observation and electron dispersive X-ray spectroscopy (EDS) analysis of ex-situ heat-treated specimen revealed that the a-Si layer and Al layer switched the positions with each other during the heat treatment, resulting the crystallization of the a-Si layer. Furthermore, the in-situ heating TEM observation and EDS analysis of as-deposited specimen revealed the mixed state of Si and Al in an a-Si/A1 film and the lateral growth of crystalline Si grain during the heating. The mechanism of AIC and switching layers were also discussed from the experimental results and the binary phase diagram of Al-Si system. © 2008 The Japan Institute of Metals.