Orientation selected epitaxy for grain enlargement of AIC poly-Si seed layers

A novel method for producing a highly-(100) orientated, large grain of poly-Si seed layer on glass by multi-round aluminum-induced crystallization (AIC) is developed. A flat 200nm poly-Si layer was first fabricated by regular AIC process to be a based layer. The second round AIC process was carried out immediately on the based layer to epitaxially grow up to a 400nm poly-Si layer by solid phase epitaxy (SPE) mechanism. The structure of enlarged epitaxial grain was examined by transmission electron microscopy (TEM), the orientation map as well as histogram of grain size from large area were performed by electron backscatter diffraction (EBSD), and the crystallinity of multi-round AIC was verified by Raman spectrometry. The lateral growth and grain suppression can be clearly observed in cross-sectional TEM analysis. The average grain size can be determined from analysis of histogram. The speed of epitaxial growth is strongly influenced by the orientation of the growth plane. We utilize this characteristic to promote the {100} proportion and reduce others to achieve a highly oriented seed-layer for followed thickening step. The population of {100} crystallographic plane is obtained statistically from orientation map and a pole figure analysis. The mechanism of the multi-round AIC will be discussed in detail in the conference.