Semiconductor device and method for manufacturing semiconductor device
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorsHideto Ohnuma, Takashi Hirose
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Abstract
An object is to provide a semiconductor device including a microcrystalline semiconductor film with favorable quality and a method for manufacturing the semiconductor device. In a thin film transistor formed using a microcrystalline semiconductor film, yttria-stabilized zirconia having a fluorite structure is formed in the uppermost layer of a gate insulating film in order to improve quality of a microcrystalline semiconductor film to be formed in the initial stage of deposition. The microcrystalline semiconductor film is deposited on the yttria-stabilized zirconia, so that the microcrystalline semiconductor film around an interface with a base particularly has favorable crystallinity while by crystallinity of the base.
Claims19
A semiconductor device comprising:
- a substrate;
- a gate electrode over the substrate;
- a gate insulating film including an yttria-stabilized zirconia film over the gate electrode;
- and
- a semiconductor film over the gate insulating film,
- wherein the semiconductor film is in contact with the yttria-stabilized zirconia film.
A semiconductor device comprising:
- a substrate;
- a gate electrode over the substrate;
- a gate insulating film including an yttria-stabilized zirconia film over the gate electrode;
- a first semiconductor film over the gate insulating film;
- a second semiconductor film over the first semiconductor film, the second semiconductor film having a depressed portion on a top surface;
- a third semiconductor film over the second semiconductor film without the depressed portion of the second semiconductor film;
- and
- a conductive film over the third semiconductor film,
- wherein the first semiconductor film is in contact with the yttria-stabilized zirconia film, and
- wherein edge portions of the third semiconductor film are located at outside of edge portions of the conductive film.
A method for manufacturing a semiconductor device, comprising:
- forming a first wiring over a substrate;
- forming an insulating film containing an yttria-stabilized zirconia film over the first wiring;
- forming a semiconductor film so as to be in contact with the yttria-stabilized zirconia film;
- forming an island-like semiconductor film by selective etching of the semiconductor film;
- and
- forming a second wiring over the island-like semiconductor film.
Dependencies are inferred from the claim text.