| 摘要 |
A method for forming a semiconductor device is provided to improve concentration of electric field by rounding a boundary between a bulb-shaped neck part and a body part. A first recess region is formed by etching a part of a semiconductor substrate(200) of a gate region. An ion implantation process is performed on an edge of a bottom part of the first recess gate region. An oxide layer spacer is formed by oxidizing a sidewall of the first recess gate region. A second recess gate region having a spherical shape is formed by performing an isotropic etch process for a bottom surface of the first recess gate region by using the oxide layer spacer as a mask. The oxide layer spacer is removed. A gate oxide layer is formed on surfaces of the first and second recess gate regions. A gate(226) including the recess gate regions is formed.
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