Oxide semiconductor device including photodiode

Patent metadata

Field	Value
Publication number	US-9236408-B2
Application number	US-201313864465-A
Country	US
Kind code	B2
Filing date	Apr 17, 2013
Priority date	Apr 25, 2012
Publication date	Jan 12, 2016
Grant date	Jan 12, 2016

Abstract

A solid-state image sensing element including a transistor with stable electrical characteristics (e.g., significantly low off-state current) is provided. Two different element layers (an element layer including an oxide semiconductor layer and an element layer including a photodiode) are stacked over a semiconductor substrate provided with a driver circuit such as an amplifier circuit, so that the area occupied by a photodiode is secured. A transistor including an oxide semiconductor layer in a channel formation region is used as a transistor electrically connected to the photodiode, which leads to lower power consumption of a semiconductor device.

First claim

What is claimed is:

1. A semiconductor device comprising:
a driver circuit comprising a first transistor comprising a first channel formation region, the first transistor being provided on a top surface of a semiconductor substrate;
a second transistor comprising an oxide semiconductor layer including indium in a second channel formation region over the first transistor; and
a photodiode over the second transistor, the photodiode being electrically connected to the second transistor,
wherein a gate electrode layer of the second transistor overlaps a gate electrode layer of the first transistor when seen from a direction perpendicular to the top surface of the semiconductor substrate.

2. The semiconductor device according to claim 1 ,
wherein the photodiode overlaps the second transistor.

3. The semiconductor device according to claim 2 ,
wherein the photodiode overlaps the first transistor.

4. The semiconductor device according to claim 1 ,
wherein the first channel formation region comprises crystalline silicon.

5. The semiconductor device according to claim 1 ,
wherein a semiconductor layer of the photodiode comprises crystalline silicon.

6. The semiconductor device according to claim 1 ,
wherein the photodiode comprises a p-type semiconductor region, an i-type semiconductor region, and an n-type semiconductor region.

7. A semiconductor device comprising:
a driver circuit comprising a first transistor comprising a first channel formation region, the first transistor being provided on a top surface of a semiconductor substrate;
a second transistor comprising an oxide semiconductor layer including indium in a second channel formation region over the first transistor;
a third transistor comprising an oxide semiconductor layer including indium in a third channel formation region over the semiconductor substrate; and
a photodiode over the second transistor and the third transistor, the photodiode being electrically connected to one of a source and a drain of the second transistor,
wherein the other of the source and the drain of the second transistor is electrically connected to the third transistor and to a gate electrode layer of the first transistor, and
wherein a gate electrode layer of the second transistor overlaps the gate electrode layer of the first transistor when seen from a direction perpendicular to the top surface of the semiconductor substrate.

8. The semiconductor device according to claim 7 ,
wherein the photodiode overlaps the second transistor or the third transistor.

9. The semiconductor device according to claim 7 ,
wherein the first channel formation region comprises crystalline silicon.

10. The semiconductor device according to claim 7 ,
wherein a semiconductor layer of the photodiode comprises crystalline silicon.

11. The semiconductor device according to claim 7 ,
wherein the photodiode comprises a p-type semiconductor region, an i-type semiconductor region, and an n-type semiconductor region.

Assignees

• Semiconductor Energy Lab

Inventors

• Yamazaki Shunpei

Classifications

• H10D62/83

  being Group IV materials, e.g. B-doped Si or undoped Ge · CPC title

• H10D62/80

  characterised by the materials · CPC title

• H10D30/6755

  Oxide semiconductors, e.g. zinc oxide, copper aluminium oxide or cadmium stannate · CPC title

• H10F39/016

  of thin-film-based image sensors · CPC title

• H10F77/122

  comprising only Group IV materials · CPC title