| 摘要 |
PURPOSE:To obtain the Si gate MOS device having a short effective channel length for the subject semiconductor device by a method wherein a shallow diffusion layer having the desired low density is formed in the vicinity of a gate electrode without using an SiO2 mask on a polycrystalline Si. CONSTITUTION:A field oxide film 22 and a gate oxide film 23 are provided on a P type si substrate 21 and a polycrystalline Si 24 is superposed. A resist mask 26 is provided, films 23 and 24 are etched and an isotropic plasma etching is performed on the side face of the film 24. When the mask 26 is removed and an ion is implanted 28, an N layer 27a and an N<-> layer 27b are formed simultaneously. Lastly, the above is covered by n SiO2 film 29. According to this constitution, as a gate oxide film is used as a mask, the control of film thickness is performed easily, a diffusion layer can be formed accurately and an ion can be implanted at low accelerating voltage. By the drop of accelerating voltage., a diffusion layer with the density distribution having a sharp peak in shallow depth can be formed and a small typed Si gate FET having short effective channel length can be obtained. |
