The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Aug. 02, 2016

Filed:

Nov. 08, 2012
Applicant:

Semiconductor Energy Laboratory Co., Ltd., Atsugi-shi, Kanagawa-ken, JP;

Inventors:

Shunpei Yamazaki, Tokyo, JP;

Masayuki Sakakura, Kanagawa, JP;

Ryosuke Watanabe, Kanagawa, JP;

Junichiro Sakata, Kanagawa, JP;

Kengo Akimoto, Kanagawa, JP;

Akiharu Miyanaga, Kanagawa, JP;

Takuya Hirohashi, Kanagawa, JP;

Hideyuki Kishida, Kanagawa, JP;

Assignee:

Semiconductor Energy Laboratory Co., Ltd., Atsugi-shi, Kanagawa-ken, JP;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H01L 29/04 (2006.01); H01L 29/786 (2006.01); H01L 27/12 (2006.01);
U.S. Cl.
CPC ...
H01L 29/7869 (2013.01); H01L 27/1225 (2013.01); H01L 29/045 (2013.01); H01L 29/78606 (2013.01); H01L 29/78696 (2013.01);
Abstract

In a channel protected thin film transistor in which a channel formation region is formed using an oxide semiconductor, an oxide semiconductor layer which is dehydrated or dehydrogenated by a heat treatment is used as an active layer, a crystal region including nanocrystals is included in a superficial portion in the channel formation region, and the rest portion is amorphous or is formed of a mixture of amorphousness/non-crystals and microcrystals, where an amorphous region is dotted with microcrystals. By using an oxide semiconductor layer having such a structure, a change to an n-type caused by entry of moisture or elimination of oxygen to or from the superficial portion and generation of a parasitic channel can be prevented and a contact resistance with a source and drain electrodes can be reduced.


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