| abstract |
A method for forming a U-shaped vertical groove in a region where a channel portion of a transistor is formed and increasing the channel length with respect to the apparent channel length requires an extra photolithography step to dig the groove There was a problem in terms of cost and yield. By using a structure having a gate electrode or an insulating surface and forming a three-dimensional channel region, the channel length is three times or more, preferably five times the channel length as viewed from above. More preferably, the length is 10 times or more. [Selection] Figure 1 |