Semiconductor device

A semiconductor device, comprising:

• a mesa portion that has a semiconductor layered structure, and that extends in a predetermined direction;
• an extending portion that extends along the mesa portion and that is separated by trench grooves arranged respectively on both sides of the mesa portion;
• insulating portions that are made from an insulating material, and are arranged in the respective trench grooves;
• a conductive portion that is arranged on an upper side of the mesa portion, wherein at least one of the insulating portions adheres directly to the mesa portion, and forms a gap between the at least one of the insulating portions and the extending portion in at least a part of an extending direction of the mesa portion, the conductive portion is arranged across at least one of the insulating portions and the mesa portion, and there is a part along the extending direction of the mesa portion where the gap is not formed between the at least one of the insulation portions and the extending portion;
• and
• a wiring portion that is laid from the extending portion to reach the conductive portion through the at least one of the insulating portions, that is electrically connected to the conductive portion, and that is positioned on the part over the at least one of the insulation portions and on parts other than the part over the at least one of the insulation portions such that there is no insulation portion on which the wiring portion is not provided.