| 摘要 |
PURPOSE:To suppress a short channel effect sufficiently, by continuously changing the thickness of a recrystallized silicon layer of an element forming part on a substrate, and making the film thickness thinner than a source region and a drain region than a gate region. CONSTITUTION:A silicon island 32 is formed on an insulating film (SiO2) 31. A PSG33 is formed on the island. Heat treatment is performed in an N2 atmosphere, and the PSG33 is softened and made gentle. Polysilicon is deposited on the surface of the PSG33. The polysilicon layer 34 is deposited and formed along the shape of the ground surface. Then, with a substrate being heated, laser is projected, and the polysilicon layer 34 is fused and recrystallized. In this process, the surface of the recrystallized silicon 35 becomes flat. The recrystallized silicon layer 35, whose thickness is continuously changed, is obtained. A source and a drain are formed in correspondence with gate polysilicon by self-aligning. Thus an SOI type MOS FET, wherein the thickness of the silicon film itself in the element forming part is continuously changed between a source region 36, a gate region 40, and a drain region 37, is formed on the insulating film (PSG)33. |
