MEMORY DEVICE AND ELECTRONIC DEVICE

摘要

A memory device with excellent writing performance and excellent storing performance is provided. In the memory device, a first layer overlaps with a second layer. The first layer includes a first transistor including an oxide semiconductor as an active layer. The second layer includes a second transistor and a third transistor each including an oxide semiconductor as an active layer. The off-state current of a transistor formed in the first layer is lower than the off-state current of each of a transistor formed in the second layer. The field-effect mobility of the transistor formed in the second layer is higher than the field-effect mobility of the transistor formed in the first layer.

主权项

1. A memory device comprising:
a first layer; and a second layer, wherein the first layer overlaps with the second layer, wherein the first layer comprises a first transistor comprising an oxide semiconductor as an active layer, wherein the second layer comprises a second transistor and a third transistor each comprising an oxide semiconductor as an active layer, wherein one of a source and a drain of the first transistor is electrically connected to a gate of the second transistor, wherein one of a source and a drain of the second transistor is electrically connected to one of a source and a drain of the third transistor, wherein the off-state current of the first transistor is lower than the off-state current of each of the second and third transistors, and wherein the field-effect mobility of each of the second and third transistors is higher than the field-effect mobility of the first transistor.