| 摘要 |
PURPOSE:To form a diffusion layer reaching up to the upper surface of a substrate by shaping a side wall layer to a mask layer, forming a trench through anisotropic etching and injecting a liquid silica layer with the side wall layer remaining. CONSTITUTION:An oxide film 4 is formed to the surface of a P-type silicon substrate 1, and a mask layer 3 consisting of an oxide film 5, silicon nitride film 6 and a silicon oxide film 7 is shaped. A photo-resist layer 8 is attached to the mask layer 3, and a window is bored previously to a predetermined trench forming region 2. The mask layer 3 is etched, using the layer 8 as a mask, and a window is bored to the layer 3 on the region 2. A mask layer 9 composed of an silicon nitride film is shaped onto the whole surface of the layer 3. The layer 9 is etched in an anisotropic manner to form a side wall layer 10. A trench 11 is shaped by employing the layer 3 and the layer 10 as masks. A liquid silica layer 12 containing arsenic and boron is injected into the trench 11 with the layer 10 remaining. Accordingly, an N-type diffusion layer 13 and a P-type diffusion layer 14 reaching to the upper surface of the substrate 1 can be formed. |
