| 摘要 |
PURPOSE:To absorb stress due to volume expansion caused by oxidation and prevent Si crystal from becoming defective, by providing recesses along the boundaries of porous insulating layers of Si on the surface of single crystal of Si. CONSTITUTION:Openings are made in an SiO2 layer 3 on a substrate 2 to produce diffused phosphorus layers 4. After the SiO2 layer 3 is removed, a resist mask 7 is provided and dry etching is effected to make recesses 6. The depth of each recess is set large enough to absorb stress at the time of production of an insulating film. The mask 7 is removed. Porous Si layers 5 are manufactured by nonelectrolytic chemical porous treatment. Thin silica films are coated to seal up the pores of the layers 5. A porous insulating layer 3 of Si is produced on the layers 5 under high-temperature steam. At that time, the volume of each layer 5 expands greatly but most of stress transmitted toward the region around the layer 5 is absorbed by the recess 6. For this reason, no crystal defects are caused. This results in manufacturing an excellent semiconductor device. |
