On the Controlling Mechanism of Preferential Orientation of Polycrystalline-Silicon Thin Films Grown by Aluminum-Induced Crystallization

We investigated the controlling mechanism of preferential orientation in polycrystalline silicon (poly-Si) on glass substrate by Al-induced crystallization using an in situ monitoring system and electron backscattered diffraction (EBSD) measurements. Poly-Si film with (111)-preferential orientation was obtained by the layer exchange of the initial amorphous silicon (a-Si)/Al/glass into Al/poly-Si/glass. Cross-sectional EBSD revealed that Al crystal grains are much smaller than those of Si, and randomly oriented without any epitaxial relationship between (111)-oriented Si despite the fact that (111)-oriented Si is believed to originate from epitaxial growth on γ-Al 2 O 3 /Al(111). This suggests that another mechanism such as minimization of surface energy affects the formation of (111)-oriented poly-Si.