| 摘要 |
PURPOSE:To make doping of impurities possible with accurate positioning of less than + or -1mum accuracy, by a method wherein doping is performed on the basis of a mask before and after expansion, utilizing the fact that the volume of the mask is expanded at the fixed ratio when the mask is made of compound under the fixed conditions. CONSTITUTION:An Al layer 3 is formed on the crystal surface by evaporation, and a resist pattern 4 is further formed on the layer 3. The Al layer is then processed by the method such as etching, and the resist 4 is removed to form an Al layer 3'. After that, the first desired doping of impurities is selectively performed to form n type region 8, which is deeper than the conductive type region 2, within the semiconductor crystal by the implantation of ion such as Se. Then, the Al mask 3' is expanded to form an Al mask pattern 3'' by the method such as anode oxidation, and the Al mask 3' is anode oxidized by 0.25mum so as to expand toward both sides by 0.25mum, respectively. The second desired doping of impurities is now performed utilizing the Al mask 3'' as a mask, and n<+> layers 7 are selectively formed by implanting ion such as Se. |
