| 摘要 |
<p>A method for manufacturing a semiconductor device is provided to restrain the increase of threshold voltage at edges of a channel and to improve tWR(Write Recovery Time) by applying different doping concentration according to the channel position. A groove(23) is formed by recessing a channel forming region of a substrate(21). A screen layer(24) is formed on the resultant structure including the groove. Dopants for controlling threshold voltage of a channel are implanted into the substrate. At this time, the doping concentration at the channel edge portion is lower than the doping concentration at the channel center portion by using the screen layer formed at both sidewalls of the groove.</p> |
