Semiconductor device and method for manufacturing the same

摘要

An object of an embodiment of the present invention is to manufacture a highly-reliable semiconductor device comprising a transistor including an oxide semiconductor, in which change of electrical characteristics is small. In the transistor including an oxide semiconductor, oxygen-excess silicon oxide (SiOX (X>2)) is used for a base insulating layer of a top-gate structure or for a protective insulating layer of a bottom-gate structure. By using the oxygen-excess silicon oxide, oxygen is discharged from the insulating layer, and oxygen deficiency of an oxide semiconductor layer and the interface state density between the oxide semiconductor layer and the base insulating layer or the protective insulating layer can be reduced, so that the highly-reliable semiconductor device in which change of electrical characteristics is small can be manufactured.

主权项

1. A semiconductor device comprising:
a substrate; a first insulating layer comprising silicon and oxygen over the substrate; an oxide semiconductor layer on and in contact with the first insulating layer; a source electrode and a drain electrode electrically connected to the oxide semiconductor layer; a second insulating layer over the oxide semiconductor layer, the source electrode and the drain electrode; and a gate electrode over the second insulating layer, wherein the number of oxygen atoms per unit volume of the first insulating layer is more than twice the number of silicon atoms per unit volume of the first insulating layer so as to reduce an oxygen deficiency of the oxide semiconductor layer, and wherein the gate electrode overlaps with the oxide semiconductor layer with the second insulating layer provided between the gate electrode and the oxide semiconductor layer.