Semiconductor device and method for manufacturing the same

A semiconductor device comprising:

• a first semiconductor layer which is formed above a substrate;
• a gate electrode, a source electrode, and a drain electrode which are formed in direct contact with the first semiconductor layer to be spaced from each other;
• a second semiconductor layer which is formed in direct contact with a top surface of the first semiconductor layer to cover the first semiconductor layer with the gate electrode, the source electrode, and the drain electrode exposed, and has a larger band gap than that of the first semiconductor layer;
• and
• an insulating film which is formed in direct contact with the second semiconductor layer,
• wherein the side of the gate electrode facing the drain electrode extends over the top surface of the second semiconductor layer toward the drain electrode, and the side of the gate electrode facing the drain electrode extends over the top surface of the insulating film toward the drain electrode.