Semiconductor device and method for manufacturing semiconductor device

A semiconductor device comprising:

• a first insulator comprising a first opening;
• a first conductor over the first insulator, the first conductor comprising a second opening;
• a second insulator over the first conductor, the second insulator comprising a third opening;
• an oxide positioned in the first opening, the second opening, and the third opening;
• and
• a third insulator between the oxide and the first insulator, the first conductor, and the second insulator,
• wherein a diameter of the second opening is larger than a diameter of the first opening and a diameter of the third opening,
• wherein the oxide is positioned along a side surface and a top surface of the first insulator, a side surface of the first conductor, and a bottom surface and a side surface of the second insulator with the third insulator positioned between the oxide and the first insulator, the first conductor, and the second insulator,
• wherein the oxide comprises a first region in the first opening, a second region in the second opening, and a third region in the third opening, and
• wherein the resistances of the first region and the third region are lower than the resistance of the second region.