| 摘要 |
Self-aligned floating gates are formed to have precisely defined lengths and positions. The floating gates are formed by first forming a number of shallow trench isolation regions that have substantially planar top surfaces that lie above the top surface of the semiconductor material. A layer of dielectric is formed on the semiconductor material, followed by the formation of a first layer of polysilicon. The first layer of polysilicon is then planarized so that the first layer of polysilicon is removed from the isolation regions. In subsequent steps, the polysilicon is again etched to form the floating gates. As a result of the planarization, the lengths of the floating gates are defined by the spacing between isolation regions, and the positions of the floating gates are precisely defined.
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