| 摘要 |
PURPOSE:To reduce leakage currents generated in the edge section of an isolation groove without changing impurity concentration in a gate region by forming the isolation groove, covering a base and one part of a side wall with a diffusion-resistant film and diffusing an impurity from the side wall of the isolation groove. CONSTITUTION:An N type channel stopping region 7 is formed on the base of an isolation groove 6, and a fifth SiO2 film 21 is shaped only on the inner wall of the isolatin groove 6 through a thermal oxidation method. A first photoresist film 22 is formed through a spin coating method. A first photoresist film 22' is left only in the isolation groove 6 through an anisotropic dry etching method, etc. The fifth SiO2 film 21 in a predetermined region is removed while using the first photoresist film 22' as a mask to shape a fifth SiO2 film pattern 21'. A PSG (SiO2 containing phosphorus) film is formed through a CVD method, etc., a PSG film pattern 23 is shaped through a photo-etching technique, and a BSG (SiO2 containing boron) film 24 is formed through the CVD method, etc. A P type diffusion region 25 is shaped on the P well 2 side and an N type diffusion region 26 on the N type substrate side through heat treatment. Accordingly, impurity concentration only in the edge section of the isolation groove can be increased. |
