| 摘要 |
A method of manufacturing buried gates by performing two trench-forming operations. The method includes forming a first trench in a substrate, and then forming a dielectric layer over the substrate and the interior surface of the first trench. Next, conductive material is deposited into the first trench. Thereafter, second trenches are formed crossing the first trench alternately, wherein the second trenches has a depth greater than the depth of the first trench. Subsequently, insulation material is deposited into the second trenches simultaneously forming buried gates and isolation structures. Floating and control gates are then formed over the buried gates. A similar method can be used to form buried conductive layer by omitting the formation of the dielectric layer.
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