Semiconductor device and memory device

A semiconductor device comprising:

• an oxide over a substrate;
• a first conductor and a second conductor that are over the oxide and separated from each other;
• a third conductor in contact with a part of a top surface of the first conductor;
• a fourth conductor in contact with a part of a top surface of the second conductor;
• a first insulator that is over the third conductor and the fourth conductor and comprises an opening overlapping with a region between the third conductor and the fourth conductor;
• a second insulator that is in the opening of the first insulator and in contact with another part of the top surface of the first conductor, another part of the top surface of the second conductor, a side surface of the third conductor, and a side surface of the fourth conductor;
• a third insulator that is in the opening of the first insulator and in contact with a top surface of the oxide, a side surface of the first conductor, a side surface of the second conductor, and a side surface of the second insulator;
• and
• a fifth conductor that is over the third insulator in the opening of the first insulator and comprises a region overlapping with the oxide with the third insulator therebetween,
• wherein a distance between the first conductor and the second conductor is smaller than a distance between the third conductor and the fourth conductor,
• wherein the second insulator comprises a first layer and a second layer over the first layer,
• wherein the first layer comprises a nitride insulator, and
• wherein the second layer comprises an oxide insulator.