| 摘要 |
PURPOSE:To form a pattern provided with excellent high frequency characteristic and fine dimension by a method wherein impurities are introduced into drain and source utilizing an oxide film provided with a swell as a mask. CONSTITUTION:A dope poly Si 12 with specified pattern is provided on SiO2 film 11 on Si substrate 10 to be covered with poly Si 13 withouy or with a little additive and further covered with SiO2 14. The layer 12, 13 are heat treated in inert gas diffused from the layer 12 to the layer 13. Next, the dope poly Si 12 is wet oxidized into SiO2 15 leaving non-oxidized poly Si 16 on non-depe Si. When the layer 16 is exposed by etching, the extensions 15 are left on both sides of the poly Si 12 while source 17 and drain 18 are formed under control utilizing the swells as a diffusing mask. The swell dimension may be decided in lterms of the diffusing temperature and time into the layer 13. The formation of source 17 and drain 18 may be controlled easily with high precision. The device formed by this constitution may reduce the capacity between gate, source and drain making effective channel fine with almost the same length as the gate dimension. |
