| 摘要 |
PURPOSE:To prevent reduction of the thickness of a field oxidized film due to etching and obtain the device of high performance by a method wherein a coating film of Si3N4, Al2O3, poly Si or the like having a selective etching property in relation to an SiO2 film on an island area surrounded by the field oxidized film is provided on the field oxidized film. CONSTITUTION:SiO2 102 and Si3N4 103 are laminated on P<-> type Si, resist 104 is applied thereon, etching is made, and thereby a mask 103' is prepared. After injection of B ion, wet oxidization is applied, thereby a P<+> inversion preventing layer 106 and the field oxidized film 105 are provided and Si3N4 3' is removed by plasma etching. Next, an Si3N4 mask 107 is applied onto SiO2 105 and SiO2 105 is exposed in the end part, whereby SiO2 102 is removed through etching. Then, SiO2 111 and poly Si 110 to which phosphorus is added are formed afresh selectively and subjected to wet oxidization to form SiO3 113 and further poly Si 114 to which phosphorus is added is prepared selectively through the intermediary of SiO2 115. After that, an n<+> layer 116 is provided and covered with SiO2 115, to which an electrode 118 is attached. By this constitution, the reduction of the field oxidized film due to etching in the course of processes is prevented and thus sufficiently high field-inversion voltage is ensured. |
