Patent ID: 7026215
Filing Date: 2006-04-11
Classification: H01L

Abstract:
1. A method of producing a semiconductor device, comprising the steps of: forming a trench in a surface portion of a semiconductor substrate so as to extend form a cell-to-be-formed region for forming a cell for operating as a transistor to a gate-lead-wiring-to-be-formed region; forming an oxide film on an inner surface of the trench so as to have sidewalls and a bottom wall by thermal oxidation; and forming a gate electrode in the trench insulated with at least the oxide film from the substrate, wherein, in the step of forming the trench, the trench is formed to have crystal planes of a first main portion of the sidewalls of the trench at the cell-to-be-formed region and a second main portion of the sidewalls of the trench at the gate-lead-wiring-to-be-formed region in such a manner that a first speed of forming the oxide film at the cell-to-be-formed region is smaller than a second speed of forming the oxide film at the gate-lead-wiring-to-be-formed region, wherein, in the step of forming the oxide film, the thermal oxidation is performed so as to make a first thickness of the oxide film on the inner surface of the trench at the cell-to-be-formed region thinner than a second thickness of the oxide film on the inner surface of the trench at the gate-lead-wiring-to-be-formed region, wherein the substrate includes a silicon substrate having a (100) crystal plane, wherein the first main portion of the sidewalls of the trench at the cell-to-be-formed region has the (100) crystal plane, and wherein the second main portion of the sidewalls of the trench at the gate-lead-wiring-to-be-formed region has a (110) crystal plane.