Semiconductor device and method for manufacturing semiconductor device

A semiconductor device comprising:

• a semiconductor layer;
• a first insulator over the semiconductor layer, the first insulator including an opening;
• a first conductor over the semiconductor layer;
• and
• a second conductor and a second insulator over the first conductor,
• wherein the first conductor, the second conductor, and the second insulator are positioned in the opening,
• wherein the first conductor is in contact with a top surface of the semiconductor layer at a bottom of the opening,
• wherein the second insulator is in contact with a top surface of the first conductor and a side surface of the first insulator,
• wherein the second conductor is provided in contact with the top surface of the first conductor and a side surface of the second insulator,
• wherein the second insulator includes an oxide or a nitride,
• wherein the oxide includes one kind or more kinds selected from hafnium, aluminum, boron, gallium, zinc, yttrium, zirconium, tungsten, titanium, tantalum, nickel, germanium, and magnesium, and
• wherein the nitride includes aluminum or silicon.