Memory device

A memory device comprising:

• a first conductive layer and a second conductive layer;
• a variable resistance portion provided between the first conductive layer and the second conductive layer, and having one of a low-resistance state and a high-resistance state;
• and
• a first double tunnel junction portion provided between the first conductive layer and the variable resistance portion, and including first and second tunnel insulating films, and a first nanocrystal layer provided between the first and second tunnel insulating films and including first conductive minute particles,
• wherein the first and second insulating films have different thicknesses.

A memory device comprising:

• a first conductive layer and a second conductive layer;
• a variable resistance portion provided between the first conductive layer and the second conductive layer, and having one of a low-resistance state and a high-resistance state;
• a first tunnel insulating film provided between the first conductive layer and the variable resistance portion;
• and
• first conductive minute particles arranged in the first tunnel insulating film, and having a grain size which increases from a side adjacent to the variable resistance portion toward a side adjacent to the first conductive layer.