Semiconductor device having a backlight and light-receiving element

Patent metadata

Field	Value
Publication number	US-10095076-B2
Application number	US-201715432128-A
Country	US
Kind code	B2
Filing date	Feb 14, 2017
Priority date	Jan 15, 2010
Publication date	Oct 9, 2018
Grant date	Oct 9, 2018

Abstract

A semiconductor device includes a photodiode, a first transistor, and a second transistor. The photodiode has a function of supplying a charge corresponding to incident light to a gate of the first transistor, the first transistor has a function of accumulating the charge supplied to the gate, and the second transistor has a function of retaining the charge accumulated in the gate of the first transistor. The second transistor includes an oxide semiconductor.

First claim

The invention claimed is:

1. A semiconductor device comprising:
a substrate;
a backlight;
a light-receiving element;
a first transistor; and
a second transistor,
wherein the light-receiving element is electrically connected to a gate of the first transistor through the second transistor,
wherein each of the first transistor and the second transistor comprises a crystalline oxide semiconductor in a channel formation region,
wherein the crystalline oxide semiconductor comprises indium, gallium and zinc,
wherein an off-state current of the second transistor per micrometer of a channel width is 10 aA/μm or less,
wherein the light-receiving element is provided over the substrate,
wherein the backlight is provided under the substrate, and
wherein the light-receiving element is configured to receive a light emitted from the backlight.

2. The semiconductor device according to claim 1 , wherein the light-receiving element is a photodiode.

3. The semiconductor device according to claim 1 , wherein the light-receiving element comprises a single crystal semiconductor.

4. The semiconductor device according to claim 1 , wherein the crystalline oxide semiconductor is an intrinsic or substantially intrinsic semiconductor.

5. The semiconductor device according to claim 1 , wherein the off-state current is a current at 15° C. to 25° C. inclusive.

6. The semiconductor device according to claim 1 , further comprising an insulating layer over the first transistor,
wherein the second transistor is provided over the insulating layer, and
wherein the second transistor overlaps with the light-receiving element at least partly.

7. A semiconductor device comprising:
a substrate;
a backlight;
a light-receiving element;
a first transistor;
a second transistor; and
a third transistor,
wherein the light-receiving element is electrically connected to a gate of the first transistor through the second transistor,
wherein one of a source and a drain of the third transistor is electrically connected to the gate of the first transistor,
wherein each of the first transistor, the second transistor and the third transistor comprises a crystalline oxide semiconductor in a channel formation region,
wherein the crystalline oxide semiconductor comprises indium, gallium and zinc,
wherein an off-state current of the second transistor per micrometer of a channel width is 10 aA/μm or less,
wherein the light-receiving element is provided over the substrate,
wherein the backlight is provided under the substrate, and

wherein the light-receiving element is configured to receive a light emitted from the backlight.

8. The semiconductor device according to claim 7 , wherein the light-receiving element is a photodiode.

9. The semiconductor device according to claim 7 , wherein the light-receiving element comprises a single crystal semiconductor.

10. The semiconductor device according to claim 7 , wherein the crystalline oxide semiconductor is an intrinsic or substantially intrinsic semiconductor.

11. The semiconductor device according to claim 7 , wherein the off-state current is a current at 15° C. to 25° C. inclusive.

12. The semiconductor device according to claim 7 , further comprising an insulating layer over the first transistor,
wherein the second transistor is provided over the insulating layer, and
wherein the second transistor overlaps with the light-receiving element at least partly.

13. A semiconductor device comprising:
a substrate;
a backlight;
a light-receiving element;
a first transistor;
an insulating layer over the light-receiving element and the first transistor; and
a second transistor over the insulating layer,
wherein the light-receiving element is electrically connected to the second transistor through an electrode,
wherein the electrode is provided in an opening of the insulating layer,
wherein the second transistor comprises a crystalline oxide semiconductor in a channel formation region,
wherein the crystalline oxide semiconductor comprises indium, gallium and zinc,
wherein an off-state current of the second transistor per micrometer of a channel width is 10 aA/μm or less,
wherein the light-receiving element is provided over the substrate,
wherein the backlight is provided under the substrate, and

wherein the light-receiving element is configured to receive a light emitted from the backlight.

14. The semiconductor device according to claim 13 , wherein the light-receiving element is a photodiode.

15. The semiconductor device according to claim 13 , wherein the light-receiving element comprises a single crystal semiconductor.

16. The semiconductor device according to claim 13 , wherein the crystalline oxide semiconductor is an intrinsic or substantially intrinsic semiconductor.

Assignees

• Semiconductor Energy Lab

Inventors

• Kurokawa Yoshiyuki
• Ikeda Takayuki

Classifications

• G02F1/133345

  Insulating layers (G02F1/1335, G02F1/1337, G02F1/135, G02F1/136 take precedence) · CPC title

• G09G2360/145

  the light originating from the display screen · CPC title

• G02F2202/10

  semiconductor · CPC title

• G02F1/1362

  Active matrix addressed cells {(G02F1/134336, G02F1/134363 take precedence)} · CPC title

• G09G3/3648

  using an active matrix (G09G3/367 - G09G3/3696 take precedence) · CPC title