Semiconductor device and semiconductor memory device

A semiconductor device, comprising:

• a first electrode;
• a second electrode;
• an oxide semiconductor layer provided between the first electrode and the second electrode and including a first region, a second region, and a third region disposed between the first region and the second region;
• a gate electrode facing the third region;
• a first insulating layer facing the first region;
• a second insulating layer facing the second region;
• and
• a gate insulating layer provided between the gate electrode and the oxide semiconductor layer, between the first insulating layer and the oxide semiconductor layer, and between the second insulating layer and the oxide semiconductor layer, the gate insulating layer containing oxygen (O) and at least one metal element selected from a group consisting of aluminum (Al), hafnium (Hf), zirconium (Zr), lanthanum (La), yttrium (Y), zinc (Zn), indium (In), tin (Sn), and gallium (Ga), and the gate insulating layer having a chemical composition different from a chemical composition of the oxide semiconductor layer,
• wherein the gate insulating layer contains silicon (Si) and nitrogen (N), and
• wherein a ratio of an atomic concentration of the at least one metal element to an atomic concentration of nitrogen in the gate insulating layer provided between the first insulating layer and the oxide semiconductor layer is higher than a ratio of an atomic concentration of the at least one metal element to an atomic concentration of nitrogen in the gate insulating layer provided between the gate electrode and the oxide semiconductor layer, or a ratio of an atomic concentration of the at least one metal element to an atomic concentration of nitrogen in the gate insulating layer provided between the second insulating layer and the oxide semiconductor layer is higher than the ratio of the atomic concentration of the at least one metal element to the atomic concentration of nitrogen in the gate insulating layer provided between the gate electrode and the oxide semiconductor layer.

A semiconductor device, comprising:

• a first electrode;
• a second electrode;
• an oxide semiconductor layer provided between the first electrode and the second electrode and electrically connected to the first electrode and the second electrode;
• a gate electrode surrounding the oxide semiconductor layer;
• and
• a gate insulating layer provided between the gate electrode and the oxide semiconductor layer, the gate insulating layer containing oxygen (O) and at least one metal element selected from a group consisting of aluminum (Al), hafnium (Hf), zirconium (Zr), lanthanum (La), yttrium (Y), zinc (Zn), indium (In), tin (Sn), and gallium (Ga), and the gate insulating layer having a chemical composition different from a chemical composition of the oxide semiconductor layer.