Ion-Assisted Low-Temperature Silicon Epitaxy on Randomly Textured Seed Layers on Glass

Ion-assisted deposition (IAD) of silicon at a substrate temperature of 630 °C was used for thickening a crystalline silicon seed layer made on glass by aluminum-induced crystallization (AIC) of amorphous silicon. The seed layer consists of randomly oriented crystal grains whose crystallographic orientations with respect to the substrate's normal were determined with cross-sectional transmission electron microscopy (TEM) by analyzing their Kikuchi diffraction patterns. As shown by the TEM analysis, the IAD film grown on the AIC seed layer continues epitaxially the crystallographic structure of the seed layer. The crystallographic orientation of the seed layer does not appear to play the dominant role in determining the crystal quality of the subsequently grown IAD film. The fabrication of continuous AIC seed layers results in the production of island-like silicon protrusions on the surface of the seed layer. The impact of these “islands” on the subsequent IAD growth was investigated by comparison to the growth on similarly oriented island-free regions of the AIC seed layer. It is concluded that the IAD material grown on top of the AIC islands is of similar structural quality as the IAD material grown on island-free grains.