To whom interested in Research & Development and/or Business Development of IGZO-based Oxide Semiconductor TFT

In reply to recent numerous inquiries for JST, we are pleased to explain the background of the inventions and the outline of the licensable package patents from JST, with regard to the invention of "IGZO-TFT" made by Professor Hideo Hosono at Tokyo Tech, et al.

JST, in its technology transfer program, supports patent acquisition and undertakes licensing activities to achieve commercialization of research outputs from JST programs. As a part of this program, JST has already concluded license agreements on the said technologies with domestic and international corporations, and is in the process of negotiation with other corporations.

The said technology is the world-first invention on IGZO-TFT created in the JST's ERATO*3) "Hosono Transparent ElectroActive Materials Project *4) and subsequent ERATO-SORST Project “Electro-Active Function Cultivation in Transparent Oxides Utilizing Built-in Nanostructures”^*5), where Professor Hideo Hosono played as the leader from 1999. JST has been offering the package licensing program with dozens of patents to industry, together with other closely-related patents and inventions created by entities such as Tokyo Tech.

*5) http://www.jst.go.jp/kisoken/sorst/hyouka/2009/pdf/h21%20hosono.pdf (Japanese)

Historical background on A) Existing major technologies and B) Technologies related to our patent package including the related academic papers are summarized as follows;

A) Existing major technologies

1) December, 1985

Polycrystalline IGZO (InGaZnO₄, In₂Ga₂ZnO₇) was synthesized for the first time, and its space group determined by powder X-ray diffraction was reported.
“Spinel, YbFe₂O₄, and Yb₂Fe₃O₇ types of structures for compounds in the In₂O₃ and Sc₂O₃, A₂O₃,BO systems [A: Fe, Ga, or Al; B: Mg, Mn, Fe, Ni, Cu, or Zn] at temperatures over 1000℃”
(N. Kimizuka and T. Mohri, J. Sol. State Chem. 60, 382 (1985): http://dx.doi.org/10.1016/0022-4596(85)90290-7)

2) April, 1995

Single-crystal IGZO was synthesized, and its crystal structure as a homologous series layered one was reported for the first time.
“Syntheses and Single-Crystal Data of Homologous Compounds, In₂O₃(ZnO)_m (m = 3, 4, and 5), InGaO₃(ZnO)₃, and Ga₂O₃(ZnO)_m (m = 7, 8, 9, and 16) in the In₂O₃-ZnGa₂O₄-ZnO System”
(N. Kimizuka, M. Isobe, and M. Nakamura, J. Sol. State Chem. 60, 382 (1985): http://dx.doi.org/10.1006/jssc.1995.1198)

3) November, 1995

Electrical conduction and opto-electronic properties of bulk polycrystalline IGZO were firstly reported.
“New Transparent Conductive Oxides with YbFe₂O₄ Structure”
(M. Orita et al., Jpn. J. Appl. Phys. 34, L1550 (1995): http://jjap.jsap.jp/link?JJAP/34/L1550/)

B) Technologies related to our patent package

1) March, 1995

The invention on c-axis-oriented polycrystalline IGZO thin films with conductive property was applied for patent. (issued)

2) May and August, 1996

Working hypothesis on material design for amorphous oxide semiconductor with high electron mobility, along with example materials, was published.
“Working hypothesis to explore novel wide band gap electrically conducting amorphous oxides and examples”
(H. Hosono et al., J. Non-Cryst. Sol. 198-200, 165 (1996): http://dx.doi.org/10.1016/0022-3093(96)80019-6)
“Novel oxide amorphous semiconductors: transparent conducting amorphous oxides”
(H. Hosono et al., J. Non-Cryst. Sol. 203, 334 (1996): http://dx.doi.org/10.1016/0022-3093(96)00367-5)

3) September, 2002

The invention on IGZO-TFT with an active layer either of single-crystalline IGZO thin film or amorphous IGZO thin film was applied. (issued)

4) May, 2003

The first paper on a TFT with a c-axis-oriented epitaxial IGZO thin film was published.
“Thin-Film Transistor Fabricated in Single-Crystalline Transparent Oxide Semiconductor”
(K. Nomura et al., Science 300, 1269 (2003): http://dx.doi.org/10.1126/science.1083212)

5) March, 2004

The invention on amorphous IGZO-TFT was applied for patent. (issued)

6) November, 2004

The invention on amorphous IGZO-TFT including micro/nanocrystals in an amorphous IGZO thin film was applied for patent. (issued)

7) November, 2004

The first paper on amorphous IGZO-TFT was published.
“Room-temperature fabrication of transparent flexible thin-film transistors using amorphous oxide semiconductors”
(K. Nomura et al., Nature 432, 488 (2004); http://dx.doi.org/10.1038/nature03090)

The patent licensing package that JST is offering includes the above patents of B)-1), 3) ,5) and 6), and covers IGZO-TFT using an IGZO active layer of single-crystalline, polycrystalline, micro/nanocrystalline, and/or amorphous forms. This license package also includes related patents on materials other than In-Ga-Zn-O, impurities, device structures, manufacturing methods, devices, equipments, and related products. This wide range of coverage, in addition to the inclusion of the basic part of the invention, is another proof of the originality of "IGZO Oxide Semiconductor TFTs" existing in Professor Hideo Hosono, et al.

For further details, please consult us by email to licensejst.go.jp.

“IGZO” Trademark, free to use

1) The Trademark Act does not allow a trademark consisting solely of standard characters indicating, in a common manner, raw materials in the case of goods, to be registered (Trademark Act, Article 3, 1, (iii)). JST filed a request for invalidation trial on July 31, 2013 relating to the trademark registration of “IGZO” owned by Sharp Corporation, as “IGZO” is a commonly used raw material name. On March 5, 2014, the trial decision was rendered by Japan Patent Office (JPO) to the effect that the trademark registration of “IGZO” is to be invalidated.

2) It is reported in one of the newspapers dated April 21, 2014 that Sharp Corporation filed an appeal to the Intellectual Property High Court (IPHC) against the above decision by JPO.

3) For clarification, JST filed the request for invalidation trial on July 31, 2013, only on the registered trademark No.5451821, in which “IGZO” trademark consists solely of standard characters, however, not on the “IGZO” related registered trademarks including No.5563245 which are also owned by Sharp Corporation.

Japan Science and Technology Agency
Center for Intellectual Property Strategies
5-3, Yonbancho, Chiyoda-ku, Tokyo 102-8666 JAPAN
Phone: +81-3-5214-8486, Fax: +81-3-5214-8417
E-mail: licensejst.go.jp