| 摘要 |
PURPOSE:To contrive to increase the density and increase VTH while preventing the cut of a wiring caused by the stepwise difference of an oxide film by a method wherein a thick Si oxide layer is buried deeply into a substrate between MOS transistors. CONSTITUTION:A P type substrate 11 becomes the substrate of the channel type transistor, and an N type source and drain region 12a and 12b are formed therein. On the other hand, as the substrate of the P-channel type MOS transistor, an N-well 13 built in the P type substrate 11 is used, and the source and drain regions 14a and 14b of the P type MOS transistor are formed therein. An oxidized porous part 15 is formed by heat treatment in a high temperature oxygen atmosphere containing steam. A C-MOS integrated circuit of such a structure can be largely reduced in shape by the presence of the layer 15 produced by oxidizing porous Si. Since the layer 15 has a structure of burial under the surface of the substrate, the surface is flattened, and the trouble due to the cut of an Al film, etc. is eliminated, further the integration density increases. |
