| 摘要 |
The method forms a first nitride film on a silicon substrate, which is covered with a pad oxide film, followed by etching the nitride film, the pad oxide film and the substrate in order, so as to form a trench in a portion. A poly-silicon film is deposited entirely on the resulting structure, so as to cover the trench and the nitride film. The method also subjects the poly-silicon film to planarising, then forming a second nitride film on the planarised poly-silicon film and etching back the second film. A second etching step of etching the planarised poly-silicon film fills the trench, so as to expose a set portion of the trench. The method prevents increase of current leakage and improves reliability.
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