| 摘要 |
A method for manufacturing a nonvolatile memory includes steps of forming a first trench of a first width in a substrate of a first conductivity type, forming a second trench within the first trench, having a second width smaller than the first width of the first trench, injecting ions into a surface of the substrate and into sidewalls of the first and second trenches to adjust a threshold voltage, forming first insulating film sidewalls on the sidewalls of the first and second trenches, forming source and drain regions by injecting second conductive impurity ions into the substrate and bottom surfaces of the first and second trenches, depositing a second insulating film on the substrate, forming a floating gate and a gate electrode on sidewalls of the second insulating film within the first and second trenches, depositing a third insulating film on the substrate, and forming a control gate on sidewalls of the third insulating film at a sidewall of the first trench.
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