| 摘要 |
PURPOSE:To integrate an ultrathin-film SOI MOSFET and other elements on the same substrate by a method wherein an ultrathin-film SOI MOSFET structure whose matching property with the other elements is high is formed by using a selective oxidation method. CONSTITUTION:A resist on a silicon nitride layer 200 deposited on an oxide film layer 100 to be used as a substratum on a silicon substrate is patterned by using a photomask; the silicon nitride layer 200 is etched by using the resist as a mask; after that, the oxide film layer 100 and the silicon substrate are etched continuously. The resist is removed; after that, an oxide film 101 to be used as a substratum of a nitride film 210 is formed again on the exposed silicon surface; the silicon nitride layer 210 is deposited. A silicon nitride corresponding to a thickness of the silicon nitride layer 210 deposited nearly perpendicularly is etched on the whole surface of the substrate; a silicon nitride spacer 211 is formed on a side face of a protrusion formed by using the initial pattern 200. An oxidation operation is executed by using the silicon nitrides 200 and 211 as a mask; a thick oxide film 110 is grown only in a part where a silicon nitride mask does not exist. |
