Image pickup device, method of manufacturing image pickup device, and electronic apparatus

Patent metadata

Field	Value
Publication number	US-9502459-B2
Application number	US-201414313462-A
Country	US
Kind code	B2
Filing date	Jun 24, 2014
Priority date	Jul 1, 2013
Publication date	Nov 22, 2016
Grant date	Nov 22, 2016

Abstract

An image pickup device includes: a photodiode provided in a silicon substrate, and configured to generate electric charge corresponding to an amount of received light, by performing photoelectric conversion; and a transfer transistor provided at an epitaxial layer on the silicon substrate, and configured to transfer the electric charge generated in the photodiode, wherein the transfer transistor includes a gate electrode and a channel region, the gate electrode being embedded in the epitaxial layer, and the channel region surrounding the gate electrode, and the channel region has, in a thickness direction, a concentration gradient in which a curvature of a potential gradient is free from a mixture of plus and minus signs.

First claim

What is claimed is:

1. An image pickup device comprising:
a photodiode provided in a silicon substrate, and configured to generate electric charge corresponding to an amount of received light, by performing photoelectric conversion; and
a transfer transistor provided at an epitaxial layer on the silicon substrate, and configured to transfer the electric charge generated in the photodiode,
wherein the transfer transistor includes a gate electrode and a channel region, the gate electrode being embedded in the epitaxial layer, and the channel region surrounding the gate electrode, and
the channel region has, in a thickness direction, a concentration gradient in which a curvature of a potential gradient is free from a mixture of plus and minus signs.

2. The image pickup device according to claim 1 , wherein the channel region is formed by providing concentration distribution in the thickness direction, in a process of performing In-Situ Dope epitaxial growth.

3. The image pickup device according to claim 2 , wherein the channel region has a a concentration distribution in which a curvature of a concentration gradient in the thickness direction is free from a mixture of plus and minus signs.

4. The image pickup device according to claim 3 , wherein
the channel region is of one conductivity type in the thickness direction, and
the channel region is a single layer.

5. The image pickup device according to claim 4 , wherein
the epitaxial layer includes a trench passing through the epitaxial layer,
the gate electrode is formed to fill the trench, and
the channel region is formed on a side face of the trench and a part in proximity to the side face.

6. The image pickup device according to claim 5 , wherein
the silicon substrate includes an impurity region provided in a part of the silicon substrate, the part being immediately above the photodiode, and the impurity region having a concentration lower than an impurity concentration of the photodiode, and
a base of the trench is in contact with the impurity region.

7. An electronic apparatus comprising:
an image pickup device; and
a signal processing circuit configured to perform predetermined processing on a pixel signal outputted from the image pickup device,
wherein the image pickup device includes
a photodiode provided in a silicon substrate, and configured to generate electric charge corresponding to an amount of received light, by performing photoelectric conversion, and
a transfer transistor provided at an epitaxial layer on the silicon substrate, and configured to transfer the electric charge generated in the photodiode,
the transfer transistor includes a gate electrode and a channel region, the gate electrode being embedded in the epitaxial layer, and the channel region surrounding the gate electrode, and
the channel region has, in a thickness direction, a concentration gradient in which a curvature of a potential gradient is free from a mixture of plus and minus signs.

Assignees

• Sony Corp
• Sony Semiconductor Solutions Corp

Inventors

• Miyanami Yuki

Classifications

• H04N25/76

  Addressed sensors, e.g. MOS or CMOS sensors · CPC title

• H04N25/60

  Noise processing, e.g. detecting, correcting, reducing or removing noise · CPC title

• H01L27/14641

  Electricity · mapped topic

• H01L27/14643 Primary

  Electricity · mapped topic

• H01L27/14638

  Electricity · mapped topic