Semiconductor device and display apparatus

• US 8,513,662 B2
• Filed: 05/11/2009
• Issued: 08/20/2013
• Est. Priority Date: 05/12/2008
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Yabuta, Hisato, Ofuji, Masato, Takai, Yasuyoshi, Kawasaki, Takehiko, Kaneko, Norio, Hayashi, Ryo
• Primary Examiner(s): WOJCIECHOWICZ, EDWARD JOSEPH
• Application Number:
  US12/992,071
• Publication Number:
  US 20110062441A1
• Time in Patent Office: 1,562 Days
• Field of Search: 257/10, 257/43, 257/53, 257/59, 257/E33.004, 257/E33.037, 257/E33.053
• US Class Current: 257/43
• CPC Class Codes: H01L 29/78633 with a light shield
• CPC Class Codes: H01L 29/78645 with multiple gate

Abstract

Provided is a semiconductor device including a semiconductor element including at least a semiconductor as a component characterized by including: a mechanism for irradiating the semiconductor with light having a wavelength longer than an absorption edge wavelength of the semiconductor; and a dimming mechanism, provided in a part of an optical path through which the light passes, for adjusting at least one factor selected from an intensity, irradiation time and the wavelength of the light, wherein a threshold voltage of the semiconductor element is varied by the light adjusted by the dimming mechanism.

Claims

1. A semiconductor device comprising:

a semiconductor element including a semiconductor as a component;

a mechanism for irradiating the semiconductor with light having a wavelength longer than an absorption edge wavelength of the semiconductor; and

a dimming mechanism included in the semiconductor element, provided in a part of an optical path through which the light passes, for adjusting at least one selected from the intensity, irradiation time and wavelength of the light,

wherein a threshold voltage of the semiconductor element is varied by the light adjusted by the dimming mechanism, and

wherein the semiconductor is of amorphous In—

Ga—

Zn—

O (IGZO), amorphous In—

Zn—

O (IZO) or amorphous Zn—

Sn—

O (ZTO).

2. The semiconductor device according to claim 1, wherein the dimming mechanism absorbs or blocks light with a wavelength shorter than the absorption edge wavelength of the semiconductor.

3. The semiconductor device according to claim 1, wherein the dimming mechanism is provided between a light source for light irradiation and the semiconductor.

4. The semiconductor device according to claim 1, wherein the dimming mechanism includes one element selected from a liquid-crystal element, an electrochromic element, a color filter and an electro-optic effect element.

5. The semiconductor device according to claim 1, further comprising a mechanism for detecting the semiconductor element characteristic connected to the semiconductor element,

wherein the dimming mechanism detects a variation in the threshold voltage of the semiconductor element via the mechanism for detecting the semiconductor element, and adjusts the light based on the detected variation.

6. The semiconductor device according to claim 1, wherein the light irradiation is performed before driving of the semiconductor device.

7. The semiconductor device according to claim 1, wherein the light irradiation is performed during driving of the semiconductor device or after termination of the driving.

8. The semiconductor device according to claim 1, wherein the semiconductor element includes at least a gate electrode, a source electrode, a drain electrode, a channel layer and a gate insulation film;

and the semiconductor is the channel layer.

9. The semiconductor device according to claim 1, wherein a surface density of in-gap states in the semiconductor is no more than 10¹³ cm⁻

2 eV<sup>−

1</sup>.

10. The semiconductor device according to claim 1, wherein the semiconductor is a semiconductor with a band gap of no less than 1.55 eV.

14. The semiconductor device according to claim 2, wherein the dimming mechanism is provided between the mechanism for irradiating the semiconductor with light and the semiconductor.

15. The semiconductor device according to claim 14, wherein the dimming mechanism includes one element selected from a liquid-crystal element, an electrochromic element, a color filter and an electro-optic effect element.

11. A display apparatus comprising:

a semiconductor device as a display device, comprising;

as a display device, comprising;

a semiconductor element including a semiconductor as a component,

a mechanism for irradiating the semiconductor with light having a wavelength longer than an absorption edge wavelength of the semiconductor; and

a dimming mechanism included in the semiconductor element, provided in a part of an optical path through which the light passes, for adjusting at least one selected from the intensity, irradiation time and wavelength of the light; and

a drive element for driving the display device,

wherein a threshold voltage of the semiconductor element is varied by the light adjusted by the dimming mechanism, and

wherein the semiconductor is of amorphous In—

Ga—

Zn—

O (IGZO), amorphous In—

Zn—

O (IZO) or amorphous Zn—

Sn—

O (ZTO).

12. The display apparatus according to claim 11, wherein the display apparatus is an image display apparatus, and the mechanism for irradiating the semiconductor with light includes a backlight light source.

13. The display apparatus according to claim 11, wherein the semiconductor element includes a thin-film transistor which comprises a gate electrode, gate insulation film, a source electrode, a drain electrode and the semiconductor as a channel layer, the thin-film transistor is connected to a mechanism for detecting a TFT characteristic of the thin-film transistor, and the dimming mechanism adjusts the light based on the TFT characteristic detected by the mechanism for detecting a TFT characteristic.