Physical layout and structure of RGBZ pixel cell unit for RGBZ image sensor

Patent metadata

Field	Value
Publication number	US-10128287-B2
Application number	US-201715657276-A
Country	US
Kind code	B2
Filing date	Jul 24, 2017
Priority date	Dec 22, 2014
Publication date	Nov 13, 2018
Grant date	Nov 13, 2018

Abstract

An image sensor is described having a pixel cell unit. The pixel cell unit has first, second and third transfer gate transistor gates on a semiconductor surface respectively coupled between first, second and third visible light photodiode regions and a first capacitance region. The pixel cell unit has a fourth transfer gate transistor gate on the semiconductor surface coupled between a first infrared photodiode region and a second capacitance region.

First claim

The invention claimed is:

1. A pixel unit cell comprising:
a non-visible light photodiode region and exactly three visible light photodiode regions, wherein the non-visible light photodiode region and the exactly three visible light photodiode regions collectively form a rectangle;
a non-visible light capacitance region that is (i) associated with the non-visible light photodiode region, (ii) not associated with any other photodiode region, and (iii) formed at a corner of the non-visible light photodiode region that is shared with exactly one of the three visible light photodiode regions;
a non-visible light transfer gate positioned between the non-visible light photodiode region and the non-visible light capacitance region;
a single visible light capacitance region associated with the exactly three visible light photodiode regions; and

for each of the exactly three visible light photodiode regions, a respective visible light transistor gate positioned between the visible light photodiode region and the single visible light capacitive region at a corner of the visible light photodiode region that is shared with all of both other visible light photodiode regions and the non-visible light photodiode region, wherein no electrode is positioned between the non-visible light photodiode region and the single visible light capacitive region.

2. The pixel unit cell of claim 1 , wherein the non-visible light capacitance region is positioned at a corner of the non-visible light photodiode region that is not the shared corner of the exactly three visible light photodiode regions.

3. The pixel unit cell of claim 1 , comprising:
a non-visible light voltage supply terminal; and
a second non-visible light transfer gate positioned between the non-visible light photodiode region and the non-visible light voltage supply terminal.

4. The pixel unit cell of claim 1 , wherein the non-visible light voltage supply terminal is positioned at a corner of the non-visible light photodiode region that is not a shared corner of the exactly three visible light photodiode regions and that is adjacent to a corner of the non-visible light photodiode region in which the non-visible light capacitance region is positioned.

5. The pixel unit cell of claim 1 , wherein the non-visible light voltage supply terminal is positioned at a corner of the non-visible light photodiode region that is not a shared corner of the exactly three visible light photodiode regions and that is opposite to a corner of the non-visible light photodiode region in which the non-visible light capacitance region is positioned.

6. The pixel unit cell of claim 1 , comprising:
exactly three visible light voltage supply terminals, comprising a first visible light voltage supply terminal that is associated with a first subset of the visible light photodiode regions of the pixel cell and a first subset of visible light photodiode regions of an adjacent pixel cell, and a second visible light voltage supply terminal that is associated with a second subset of the visible light photodiode regions of the pixel cell and a first subset of visible light photodiode regions of a different, adjacent pixel cell; and
for each of the exactly three visible light photodiode regions, an additional respective visible light transistor gate positioned between the visible light photodiode region and one of the exactly three visible light voltage supply terminals.

7. A method comprising:
forming a non-visible light photodiode region and exactly three visible light photodiode regions on a semiconductor surface, wherein the non-visible light photodiode region and the exactly three visible light photodiode regions collectively form a rectangle;
forming a non-visible light capacitance region that is associated with the non-visible light photodiode region and is not associated with any other photodiode region, on the semiconductor surface at a corner of the non-visible light photodiode region that is shared with exactly one of the three visible light photodiode regions;
forming a non-visible light transfer gate positioned between the non-visible light photodiode region and the non-visible light capacitance region on the semiconductor surface;
forming a single visible light capacitance region associated with the multiple visible light photodiode regions on the semiconductor surface; and
for each of the exactly three visible light photodiode regions, forming a respective visible light transistor gate positioned between the visible light photodiode region and the single visible light capacitive region on the semiconductor surface at a corner of the visible light photodiode region that is shared with all of both other visible light photodiode regions and the non-visible light photodiode region, wherein no electrode is positioned between the non-visible light photodiode region and the single visible light capacitive region.

8. The method of claim 7 , wherein the non-visible light capacitance region is positioned at a corner of the non-visible light photodiode region that is not the shared corner of the exactly three visible light photodiode regions.

9. The method of claim 7 , comprising:
forming a non-visible light voltage supply terminal; and
forming a second non-visible light transfer gate positioned between the non-visible light photodiode region and the non-visible light voltage supply terminal.

10. The method of claim 7 , wherein the non-visible light voltage supply terminal is positioned at a corner of the non-visible light photodiode region that is not a shared corner of the exactly three visible light photodiode regions and that is adjacent to a corner of the non-visible light photodiode region in which the non-visible light capacitance region is positioned.

11. The method of claim 7 , wherein the non-visible light voltage supply terminal is positioned at a corner of the non-visible light photodiode region that is not a shared corner of the exactly three visible light photodiode regions and that is opposite to a corner of the non-visible light photodiode region in which the non-visible light capacitance region is positioned.

12. The method of claim 7 , comprising:
forming exactly three visible light voltage supply terminals on the semiconductor surface, comprising forming a first visible light voltage supply terminal that is associated with a first subset of the visible light photodiode regions of the pixel cell and a first subset of visible light photodiode regions of an adjacent pixel cell, and forming a second visible light voltage supply terminal that is associated with a second subset of the visible light photodiode regions of the pixel cell and a first subset of visible light photodiode regions of a different, adjacent pixel cell; and
for each of the exactly three visible light photodiode regions, forming an additional respective visible light transistor gate positioned between the visible light photodiode region and one of the exactly three visible light voltage supply terminals on the semiconductor surface.

Assignees

• Google Llc

Inventors

• Wan Chung Chun
• Fowler Boyd Albert

Classifications

• H04N25/778

  comprising amplifiers shared between a plurality of pixels, i.e. at least one part of the amplifier must be on the sensor array itself · CPC title

• H04N23/11

  for generating image signals from visible and infrared light wavelengths · CPC title

• H04N25/705

  Pixels for depth measurement, e.g. RGBZ · CPC title

• H04N25/134

  based on three different wavelength filter elements · CPC title

• H04N23/57

  Mechanical or electrical details of cameras or camera modules specially adapted for being embedded in other devices · CPC title