| 摘要 |
PURPOSE: To oxidize a trench side wall to various thicknesses corresponding to the need of a trench IC by depositing and removing a silicon nitride coating on a first oxide layer formed on the entire surface of a trench, exposing a first oxide, etching the exposed part and selectively oxidizing it to a second thickness different from a first thickness. CONSTITUTION: The first oxide layer over the selectively oxidized entire trench surface area of the trench side wall is grown to the side wall 1 of a prescribed thickness. Thereafter, silicon nitride is vapor deposited on the first layer of the oxide of the trench. The selected side wall of the trench is scratched by ion implantation and the damaged part of the silicon nitride is etched. Then, the exposed first oxide layer is wet-etched and selectively oxidized so as to be the side wall 2 thicker than the side wall 1. Thus, the trench side wall is individually oxidized to a desired thickness.
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