| 摘要 |
<p>PURPOSE:To enhance the mobility of carrier in a thin film by heat treating an amorphous silicon thin film formed on a substrate thereby forming thin film polycrystalline silicon such that no crystal grain boundary is present in the direction of thickness. CONSTITUTION:A first amorphous silicon layer 22, doped with P through diffusion of a crystal phase 23, is formed on a substrate 21 by plasma CVD. An undoped second amorphous silicon layer 24 is then formed thereon by plasma CVD. Heat treatment is then conducted in vacuum or nitrogen atmosphere for 3-20 hours at 550-650 deg.C in order to crystallize the amorphous silicon layers 22, 24 thus formed. Consequently, the crystal phase 23 becomes the seed for starting the crystallization which progresses along the direction of thickness thus growing grains 25. The grains 25 eventually spread over the entire region of the amorphous silicon layers 22, 24 thus forming thin film polycrystalline silicon.</p> |
