摘要 |
A fabrication method provides a single electron transistor with a reduced quantum dot size. The method includes the steps of forming a first gate insulating film on a semiconductor substrate, implanting impurity ions into source/drain regions of the semiconductor substrate to form source/drain impurity regions, forming a lower gate on the first gate insulating film over a channel region between the source/drain impurity regions, forming a second gate insulating film on the lower gate and the first gate insulating film, forming a third insulating film on the second gate insulating film, selectively removing a portion of the third insulating film over the channel region in a direction perpendicular to a direction between the source/drain impurity regions to define a groove in the third insulating film, and forming an upper gate in he groove of the third insulating film.
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