US 8,557,641 B2 · Semiconductor device and method for manufacturing the same

Abstract

An object is to provide a high reliable semiconductor device including a thin film transistor having stable electric characteristics. In a method for manufacturing a semiconductor device including a thin film transistor in which an oxide semiconductor film is used for a semiconductor layer including a channel formation region, heat treatment (which is for dehydration or dehydrogenation) is performed so as to improve the purity of the oxide semiconductor film and reduce impurities such as moisture. Besides impurities such as moisture existing in the oxide semiconductor film, heat treatment causes reduction of impurities such as moisture existing in the gate insulating layer and those in interfaces between the oxide semiconductor film and films which are provided over and below the oxide semiconductor film and are in contact with the oxide semiconductor film.

Claims17

Dependent claims

A method for manufacturing a semiconductor device comprising the steps of:

forming an oxide semiconductor layer over an insulating layer;
heating the oxide semiconductor layer under an inert atmosphere at a temperature equal to or higher than 450° C. to increase a carrier concentration in the oxide semiconductor layer to 1×1018 cm−3 or more;
and
forming an oxide insulating layer to reduce a carrier concentration in at least a part of the oxide semiconductor layer in contact with the oxide insulating layer to less than 1×1018 cm−3,
wherein, after heating, a hydrogen concentration in the oxide semiconductor layer is less than 3×1020 cm−3.

2 more elements

Dependencies are inferred from the claim text.

Semiconductor device and method for manufacturing the same

Life of this patent

Semiconductor device and method for manufacturing the same

Life of this patent

Abstract

Claims17