Photodetector
A photodetector according to an embodiment of the present disclosure including a plurality of photoelectric conversion sections that is provided to a semiconductor substrate. The photoelectric conversion sections each include a first region of a first electrical conduction type that is provided on a first surface side of the semiconductor substrate, a second region of a second electrical conduction type that is provided on a second surface side of the semiconductor substrate opposite to the first surface, a third region of a third electrical conduction type that is provided in a region between the first region and the second region of the semiconductor substrate, a first electrode that extends from the second surface in a thickness direction of the semiconductor substrate, a pixel separation layer having an insulation property, and a second electrode that is electrically coupled to the second region from the second surface side. The third region absorbs incident light. The first electrode is electrically coupled to the first region on a bottom surface. The pixel separation layer is provided to a side surface of the first electrode.
1. A photodetector, comprising:
a plurality of photoelectric conversion sections that is provided to a semiconductor substrate, wherein the photoelectric conversion sections comprise:
a first region of a first electrical conduction type that is provided on a first surface side of the semiconductor substrate;
a second region of a second electrical conduction type that is provided on a second surface side of the semiconductor substrate opposite to the first surface side of the semiconductor substrate;
a third region of a third electrical conduction type that is provided in a region between the first region and the second region of the semiconductor substrate, the third region directly abutting the first region and the second region and absorbing incident light;
a first electrode extending adjacent a portion of the third region from the second surface side of the semiconductor substrate, the first electrode being electrically coupled to the first region on bottom surfaces thereof;
a pixel separation layer having an insulation property, the pixel separation layer being provided between and abutting side surfaces of the first electrode and the third region; and
a second electrode that is electrically coupled to the second region on the second surface side of the semiconductor substrate.
2. The photodetector according to claim 1 , further comprising:
an upper first electrode that extends from the bottom surface of the first electrode to the first surface side of the semiconductor substrate, the upper first electrode being less than the first electrode in width; and
an upper pixel separation layer having an insulation property, the upper pixel separation layer being provided to a side surface of the upper first electrode between the upper first electrode and the first region.
3. The photodetector according to claim 1 , wherein the first electrode and the pixel separation layer are provided between adjacent photoelectric conversion sections.
4. The photodetector according to claim 3 , wherein the first electrode is electrically coupled to the first region of each of the adjacent photoelectric conversion sections on bottom surfaces thereof.
5. The photodetector according to claim 1 , wherein formation depth of the first electrode from the second surface side of the semiconductor substrate is greater than formation depth of the second region from the second surface side of the semiconductor substrate.
6. The photodetector according to claim 1 , further comprising a gate electrode that is provided on the second surface side of the semiconductor substrate with a gate insulating film interposed in between.
7. The photodetector according to claim 6 , wherein the gate electrode comprises a vertical gate electrode that is provided by digging the semiconductor substrate in a thickness direction.
8. The photodetector according to claim 1 , further comprising a potential control region of the first electrical conduction type that is provided on the second surface side of the semiconductor substrate with the second region and an insulating layer interposed in between, the potential control region being configured to control a potential.
9. The photodetector according to claim 1 , wherein the first regions and the second regions are different from each other between the respective photoelectric conversion sections in formation depth in a thickness direction of the semiconductor substrate.
10. The photodetector according to claim 1 , further comprising a multilayer wiring layer that is stacked on the second surface of the semiconductor substrate.
11. The photodetector according to claim 10 , wherein the multilayer wiring layer comprises a light shielding structure that extends in an in-plane direction of the semiconductor substrate.
12. The photodetector according to claim 1 , further comprising an uneven structure that is provided to the first surface of the semiconductor substrate, the uneven structure scattering or diffracting the incident light.
13. The photodetector according to claim 1 , further comprising:
a floating diffusion region of the second electrical conduction type that is provided on the second surface side of the semiconductor substrate; and
a transfer gate transistor that is provided between the second region and the floating diffusion region, the transfer gate transistor controlling transfer of electric charge from the second region to the floating diffusion region.
14. The photodetector according to claim 13 , further comprising:
an overflow drain region of the second electrical conduction type that is provided on an opposite side to the floating diffusion region with the second region interposed in between; and
an overflow gate transistor that is provided between the second region and the overflow drain region, the overflow gate transistor controlling transfer of electric charge from the second region to the overflow drain region.
15. The photodetector according to claim 1 , further comprising a pinning layer that is provided at an interface between the semiconductor substrate and an insulative material, wherein the pinning layer comprises a layer having an electrostatic property or a layer of the second electrical conduction type.
16. The photodetector according to claim 1 , further comprising:
a fourth region of the first electrical conduction type that is provided closer to the first surface side than the second region, the fourth region being provided in contact with the second region; and
an insulating layer that surrounds a junction surface between the second region and the fourth region in an in-plane direction of the semiconductor substrate.
17. The photodetector according to claim 1 , further comprising:
a fourth region of the first electrical conduction type that is provided closer to the first surface side than the second region, the fourth region being provided in contact with the second region; and
a fifth region of the second electrical conduction type that is provided closer to the second surface side than the first region, the fifth region being provided in contact with the first region.
18. The photodetector according to claim 1 , wherein a plurality of the photoelectric conversion sections comprises the photoelectric conversion section of a reference pixel and the photoelectric conversion section of a normal pixel, the reference pixel being provided with a light shielding section on an incidence surface of the incident light, the normal pixel not being provided with the light shielding section.
19. The photodetector according to claim 18 , wherein the reference pixel is provided to be adjacent to the normal pixel.
20. The photodetector according to claim 1 , wherein the first electrode comprises a cathode electrode and the second electrode includes an anode electrode.