Photodetection device and photodetection system

Patent metadata

Field	Value
Publication number	US-10497818-B2
Application number	US-201715656490-A
Country	US
Kind code	B2
Filing date	Jul 21, 2017
Priority date	Jul 29, 2016
Publication date	Dec 3, 2019
Grant date	Dec 3, 2019

Abstract

A semiconductor substrate has a first surface and a second surface which is opposite to the first surface. A photoelectric conversion portion has a PN junction configured with first and second semiconductor regions of different conductivity types. A buried portion is buried in the semiconductor substrate and includes an electrode and a dielectric member located between the electrode and the semiconductor substrate and in contact with the second semiconductor region. The second semiconductor region is located in a position deeper than the first semiconductor region. The buried portion is located to extend from a first surface to a position deeper than the first semiconductor region. Electric potentials are supplied to the first semiconductor region, the second semiconductor region, and the electrode in such a manner that an inversion layer occurring between the electrode and the second semiconductor region and the first semiconductor region are in contact with each other.

First claim

What is claimed is:

1. A photodetection device comprising:
a semiconductor substrate having a first surface and a second surface which is opposite to the first surface;
a photoelectric conversion portion having a PN junction configured with a first semiconductor region and a second semiconductor region of a conductivity type different from that of the first semiconductor region; and
a buried portion buried in the semiconductor substrate and including an electrode and a dielectric member which is located between the electrode and the semiconductor substrate and is in contact with the second semiconductor region,
wherein the second semiconductor region is located in a position deeper than the first semiconductor region with respect to the first surface,
wherein the buried portion is located to extend from the first surface to a position deeper than the first semiconductor region with respect to the first surface, and
wherein electric potentials are supplied to the first semiconductor region, the second semiconductor region, and the electrode in such a manner that an inversion layer occurring at the second semiconductor region in the vicinity of the dielectric member is in contact with the first semiconductor region.

2. The photodetection device according to claim 1 ,
wherein the first semiconductor region and a first portion of the dielectric member are in contact with each other, and
wherein the second semiconductor region and a second portion of the dielectric member are in contact with each other.

3. The photodetection device according to claim 2 , wherein, when a signal electric charge that is generated by the photoelectric conversion portion is an electron, an electric potential equal to or higher than the electric potential to be supplied to the second semiconductor region is supplied to the electrode, and, when the signal electric charge is a hole, an electric potential equal to or lower than the electric potential to be supplied to the second semiconductor region is supplied to the electrode.

4. The photodetection device according to claim 1 , wherein a contact plug used to supply an electric potential to the first semiconductor region is connected to the first semiconductor region.

5. The photodetection device according to claim 1 , wherein an electric potential difference between the electric potential to be supplied to the first semiconductor region and the electric potential to be supplied to the second semiconductor region is 6 V or higher.

6. The photodetection device according to claim 1 , wherein an electric potential difference between the electric potential to be supplied to the first semiconductor region and the electric potential to be supplied to the second semiconductor region is configured to become higher than a breakdown voltage.

7. The photodetection device according to claim 1 , wherein an electric potential difference between the electric potential to be supplied to the first semiconductor region and the electric potential to be supplied to the second semiconductor region is configured to become equal to or lower than a breakdown voltage.

8. The photodetection device according to claim 1 , wherein a distance between the first semiconductor region and the dielectric member is 0.1 μm or less.

9. The photodetection device according to claim 1 , wherein the photoelectric conversion portion configures an avalanche diode.

10. The photodetection device according to claim 1 , wherein the buried portion is located to extend to a position deeper than a depletion layer region that is formed by the PN junction.

11. The photodetection device according to claim 1 ,
wherein the buried portion has
a bottom portion located at a position deepest with respect to the first surface,
a side surface which is in contact with the second semiconductor region, and
an end portion connecting to the bottom portion and the side surface, and

wherein the bottom portion and the end portion are in contact with a third semiconductor region of the same conductivity type as that of the first semiconductor region.

12. The photodetection device according to claim 1 , wherein the buried portion is located to extend from the first surface to the second surface.

13. The photodetection device according to claim 1 , wherein the second semiconductor region includes
a first region which is a region having a first impurity concentration,
a second region which is a region located at a position deeper than the first region with respect to the first surface and having a second impurity concentration lower than the first impurity concentration, and
a third area which is a region located at a position deeper than the first region and the second region with respect to the first surface and having a third impurity concentration higher than the first impurity concentration and the second impurity concentration.

14. The photodetection device according to claim 1 , wherein an electric potential V 1 to be supplied to the first semiconductor region, an electric potential V 2 to be supplied to the second semiconductor region, an electric potential Vt to be supplied to the electrode, a work function ϕ 1 of the first semiconductor region, a work function ϕ 2 of the second semiconductor region, and a work function ϕt of the electrode satisfy mathematical inequality (A) when a signal electric charge that is generated by the photoelectric conversion portion is an electron, and satisfy mathematical inequality (B) when the signal electric charge is a hole:
( V 2−ϕ2)≤( Vt−ϕt )<( V 1−ϕ1)  (A)

( V 2−ϕ2)≥( Vt−ϕt )>( V 1−ϕ1)  (B).

15. The photodetection device according to claim 1 , wherein an electric potential V 1 to be supplied to the first semiconductor region, an electric potential V 2 to be supplied to the second semiconductor region, an electric potential Vt to be supplied to the electrode, a work function ϕ 1 of the first semiconductor region, a work function ϕ 2 of the second semiconductor region, and a work function ϕt of the electrode satisfy mathematical inequality (C) when a signal electric charge that is generated by the photoelectric conversion portion is an electron, and satisfy mathematical inequality (D) when the signal electric charge is a hole:
( V 2−ϕ2)<( V 1−ϕ1)≤( Vt−ϕt )  (C)

( V 2−ϕ2)≥( V 1−ϕ1)≥( Vt−ϕt )  (D).

16. The photodetection device according to claim 1 , wherein, in planar view, the first semiconductor region is located in such a way as to be enclosed by the buried portion, and
the buried portion is located in such a way as to be enclosed by the second semiconductor region.

17. The photodetection device according to claim 1 , wherein, in planar view, the first semiconductor region has a recessed portion,
the first semiconductor region is located in such a way as to be enclosed by the second semiconductor region, and
a part of the second semiconductor region and at least a part of the buried portion are located in the recessed portion.

18. The photodetection device according to claim 1 , wherein, in planar view, all around the first semiconductor region is enclosed by the buried portion, and
all around the first semiconductor region is enclosed by the second semiconductor region.

19. A photodetection system comprising:
a plurality of photodetection devices each corresponding to the photodetection device according to claim 1 ;
a wavelength conversion unit configured to convert light of a first waveband into light of a second waveband different from the first waveband; and
a signal processing unit co

Assignees

• Canon Kk

Inventors

• Morimoto Kazuhiro
• Ikeda Hajime
• Iwata Junji

Classifications

• H01G9/2027

  comprising an oxide semiconductor electrode · CPC title

• G01J1/44

  Electric circuits {(for command of an exposure part G03B7/02)} · CPC title

• H01L31/107

  Electricity · mapped topic

• H01L31/022416

  Electricity · mapped topic

• H01L31/062

  Electricity · mapped topic