| 摘要 |
PURPOSE: A method for manufacturing a semiconductor device is provided to improve a refresh characteristic by controlling an electric field between a source/drain and a gate, and to prevent the source/drain from diffusing to a lower portion of a gate electrode by forming the source/drain after a polycrystalline silicon sidewall is formed in a side surface of the gate electrode. CONSTITUTION: After a gate oxide layer(12) and a nitride layer are sequentially deposited on a substrate(11), the nitride layer is patterned to expose a partial region of the gate oxide layer. Impurity ions are implanted through the exposed gate oxide layer to form a threshold voltage control region(14) in a substrate region under the exposed gate oxide layer. Polycrystalline silicon is deposited on the entire surface of the structure, and is planarized to form a gate electrode(15) located in a region where the nitride layer is eliminated. The nitride layer is completely removed, and a polycrystalline silicon sidewall(16) is formed on a side surface of the gate electrode. A source/drain region is formed in the substrate under a side surface of the polycrystalline sidewall by an impurity ion implantation process.
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