Photodetector
A photodetector 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 is electrically coupled to the first region from the first surface side, and a second electrode that is electrically coupled to the second region from the second surface side. The third region absorbs incident light.
1 . A photodetector, comprising:
a plurality of photoelectric conversion sections that is provided to a semiconductor substrate, wherein the photoelectric conversion sections each include:
a first region of a first electrical conduction type that is provided at a first surface side of the semiconductor substrate;
a second region of a second electrical conduction type that is provided at a second surface side of the semiconductor substrate opposite to the first surface side;
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 absorbing incident light;
a first electrode that is directly electrically coupled to the first region at the first surface side, wherein the first electrode is disposed only near the first surface side of the semiconductor substrate to provide a cathode function to the photodetector;
a second electrode that is directly electrically coupled to the second region at the second surface side, wherein the second electrode is disposed only near the second surface side of the semiconductor substrate to provide an anode function to the photodetector; and
a gate electrode that is electrically coupled to the third region at the second surface side with a gate insulating film interposed in between;
wherein the first electrical conduction type is different from the second electrical conduction type;
wherein the first region is disposed directly adjacent to the third region on the first surface side of the semiconductor substrate, and wherein the second region is disposed directly adjacent to the third region on the second surface side of the semiconductor substrate.
2 . The photodetector according to claim 1 , further comprising a pixel separation layer region having an insulation property, the pixel separation layer region extending in a thickness direction of the semiconductor substrate, wherein the respective photoelectric conversion sections are electrically isolated from each other by the pixel separation layer region.
3 . The photodetector according to claim 2 , further comprising a third electrode that is provided inside adjacent to the pixel separation layer region.
4 . The photodetector according to claim 2 , further comprising a metal layer that is provided inside adjacent to the pixel separation layer region.
5 . The photodetector according to claim 2 , wherein the first electrode is provided across the pixel separation layer region on the first surface and is electrically coupled to the first regions of adjacent photoelectric conversion sections.
6 . The photodetector according to claim 1 , further comprising a wherein the gate electrode that is provided to the second surface of the semiconductor substrate with a gate insulating film interposed in between and is disposed directly adjacent to the third region.
7 . The photodetector according to claim 1 , wherein the gate electrode includes a vertical gate electrode that is provided by digging the semiconductor substrate in a thickness direction of the semiconductor substrate.
8 . The photodetector according to claim 1 , further comprising a potential control region of the first electrical conduction type that is provided at 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 side of the semiconductor substrate.
11 . The photodetector according to claim 2 , wherein the pixel separation layer region comprises a light shielding structure that prevents light from entering from adjacent pixels.
12 . The photodetector according to claim 1 , further comprising an uneven structure that is provided at 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 at 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 at 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 includes 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 the second region in an in-plane direction of the semiconductor substrate, the insulating layer being provided to reach a region that is deeper than the second region in the thickness 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 includes 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 includes a cathode electrode and the second electrode includes an anode electrode.