Semiconductor device

A semiconductor device comprising:

• a first transistor and a second transistor overlapping with each other,
• wherein the first transistor comprises:
• a semiconductor substrate comprising a source region, a drain region and a groove portion between the source region and the drain region;
• a first gate insulating film formed along a shape of the groove portion;
• and
• a gate electrode formed in the groove portion with the first gate insulating film interposed therebetween,
• wherein the second transistor comprises:
• the gate electrode formed in the groove portion;
• a second gate insulating film covering the gate electrode;
• a semiconductor film overlapping with the gate electrode with the second gate insulating film interposed therebetween;
• and
• a pair of electrodes formed in contact with the semiconductor film,
• wherein each of the pair of electrodes is a metal layer, and
• wherein one of the source region and the drain region is electrically connected to one of the pair of electrodes.