| 摘要 |
PURPOSE:To enable to form a flat insulating oxidized film even in a recess having a wide isolating width by burying an oxidized region recessed in a substrate with a silicon nitrided film and subjecting it to a vapor phase anodic oxidation. CONSTITUTION:An alumina film 3 of approx. 0.4mum thick is formed as a vapor anodic oxidation resistant material, and is patterned by ion etching, thereby forming a mask 3' which covers a non-oxidative region of an element operating region. A polysilicond film 4 is grown in chemical vapor phase in 200-500Angstrom of thickness, and a silicon nitrided film 5 is formed in approx. 0.5mum of thickness on the film 4. A primary plasma anodic oxidation is performed, thereby converting the surface of the film 5 into an oxidized film 6. When a secondary plasma anodic oxidation is performed, thereby converting the film 5 remaining only in the recess 1' and the film 4 into an oxidized film 7, which thus becomes approx. 1mum thick, and approx. 1mum of depth of the recess 1' is buried. It is eventually etched in liquid phase and is flattened. |
