| US 7,456,433 B2 | ||
| Display device and fabrication method thereof | ||
| Takuo Kaitoh, Mobara (Japan); Takahiro Kamo, Mobara (Japan); and Toshihiko Itoga, Chiba (Japan) | ||
| Assigned to Hitachi Displays, Ltd., Chiba (Japan) | ||
| Filed on Nov. 01, 2006, as Appl. No. 11/590,882. | ||
| Claims priority of application No. 2005-328865 (JP), filed on Nov. 14, 2005. | ||
| Prior Publication US 2007/0108448 A1, May 17, 2007 | ||
| Int. Cl. H01L 27/14 (2006.01); H01L 29/04 (2006.01); H01L 29/15 (2006.01); H01L 31/036 (2006.01) | ||
| U.S. Cl. 257—72 [257/59] | 6 Claims |
| 1. A display device which forms a first thin film transistor which is formed in a first region and has a first threshold value,
and a second thin film transistor which is formed in a second region and has a second threshold value which differs from the
first threshold value, wherein
the first thin film transistor has a first silicon semiconductor film,
the second thin film transistor has a second silicon semiconductor film which has different crystal structure than the first
silicon semiconductor film,
at least one of a particle size and a shape of the first silicon semiconductor film is different from that of the second silicon
semiconductor film,
first impurities and second impurities are implanted into both of a channel region of the first thin film transistor and a
channel region of the second thin film transistor,
the first impurities are substantially 100% activated in both of the channel region of the first thin film transistor and
the channel region of the second thin film transistor, and
50% or less of the second impurities are activated in the channel region of the first thin film transistor and substantially
all of the second impurities are activated in the channel region of the second thin film transistor.
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