Light receiving device and method of manufacturing light receiving device

1. A light receiving device comprising:

first semiconductor layers provided on a first main surface of a semiconductor substrate and having a first conductivity type impurity at a first concentration;

an insulating film provided between the first semiconductor layers on the first main surface;

a photoelectric conversion element provided in the first semiconductor layer;

a first electrode provided on the insulating film on the first main surface; and

a second electrode provided on a second main surface opposite the first main surface of the semiconductor substrate,

wherein the photoelectric conversion element includes:

a second semiconductor layer provided at a predetermined depth from an upper surface of the first semiconductor layer on which the first electrode is disposed and having a second conductivity type impurity at a second concentration, and

a third semiconductor layer provided within the first semiconductor layer to surround a side surface and a lower surface of the second semiconductor layer and having the first conductivity type impurity at a third concentration higher than the first concentration.

2. The light receiving device according to claim 1 ,

wherein each of the first semiconductor layer, the second semiconductor layer, and the third semiconductor layer has a rectangular shape in a plan view.

3. The light receiving device according to claim 1 ,

wherein each of the first semiconductor layer, the second semiconductor layer, and the third semiconductor layer has a rectangular shape having a rounded corner in a plan view.

4. The light receiving device according to claim 1 ,

wherein each of the first semiconductor layer, the second semiconductor layer, and the third semiconductor layer has a circular shape in a plan view.

5. The light receiving device according to claim 1 ,

wherein each of the first semiconductor layer, the second semiconductor layer, and the third semiconductor layer has an elliptical shape in a plan view.

6. The light receiving device according to claim 1 ,

wherein the first conductivity type is a P type, and

wherein the second conductivity type is an N type.

7. The light receiving device according to claim 1 ,

wherein the first conductivity type is an N type, and

wherein the second conductivity type is a P type.

8. The light receiving device according to claim 1 ,

wherein each of the first semiconductor layer, the second semiconductor layer, and the third semiconductor layer is formed of an epitaxial film.

9. The light receiving device according to claim 1 ,

wherein the photoelectric conversion element is an avalanche photodiode that operates in a Geiger mode.

10. The light receiving device according to claim 1 ,

wherein a cathode of the photoelectric conversion element is electrically connected to an electrode film via a quenching resistor.

11. The light receiving device according to claim 4 ,

wherein the semiconductor substrate is a single crystal silicon substrate, and

wherein each of the first semiconductor layer, the second semiconductor layer, and the third semiconductor layer are an epitaxial film formed of silicon.

12. A light receiving device comprising:

first semiconductor layers provided on a first main surface of a semiconductor substrate and having a first conductivity type impurity at a first concentration;

an insulating film provided between the first semiconductor layers on the first main surface;

a photoelectric conversion element provided in the first semiconductor layer;

a first electrode provided on the insulating film on the first main surface; and

a second electrode provided on a second main surface opposite the first main surface of the semiconductor substrate,

wherein the photoelectric conversion element includes:

a second semiconductor layer extending from a top height of the first semiconductor layer to a first depth and narrower than a formation range of the first semiconductor layer in a plan view and having the first conductivity type impurity at a second concentration higher than the first concentration, and

a third semiconductor layer extending from a height of the second semiconductor layer to a second depth shallower than the first depth and narrower than a formation range of the second semiconductor layer in a plan view, and a side surface and a lower surface to be surrounded by the second semiconductor layer and having a second conductivity type impurity at a third concentration.

13. A method of manufacturing a light receiving device, comprising:

forming an insulating film on a semiconductor substrate;

forming, in the insulating film, an opening reaching the semiconductor substrate;

forming, in the opening, a first semiconductor layer including a first conductivity type impurity at a first concentration;

introducing the first conductivity type impurity at a second concentration higher than the first concentration to form a second semiconductor layer, in a range from an upper surface of the first semiconductor layer to a first depth and narrower than a formation range of the first semiconductor layer in a plan view; and

introducing a second conductivity type impurity at a third concentration to form a third semiconductor layer, in a range from an upper surface of the second semiconductor layer to a second depth shallower than the first depth and narrower than a formation range of the second semiconductor layer in a plan view.