Light-receiving element and distance-measuring module
The present technology relates to a light-receiving element and a distance-measuring module for enabling improvement of characteristics. A light-receiving element includes an on-chip lens, a wiring layer, and a semiconductor layer arranged between the on-chip lens and the wiring layer, the semiconductor layer includes a first voltage application portion to which a first voltage is applied, a second voltage application portion to which a second voltage different from the first voltage is applied, a first charge detection portion arranged near the first voltage application portion, and a second charge detection portion arranged near the second voltage application portion, and each of the first voltage application portion and the second voltage application portion is covered with an insulating film in the semiconductor layer. The present technology can be applied to, for example, a light-receiving element that generates distance information by a ToF method.
1. A light-receiving element, comprising:
an on-chip lens;
a wiring layer; and
a semiconductor layer between the on-chip lens and the wiring layer, wherein
the semiconductor layer includes:
a first voltage application portion configured to receive a first voltage,
a second voltage application portion configured to receive a second voltage different from the first voltage,
a first charge detection portion around the first voltage application portion, and
a second charge detection portion around the second voltage application portion,
an insulating film that covers each of the first voltage application portion and the second voltage application portion, and
a hole concentration strengthening layer on an outer periphery of the insulating film.
2. The light-receiving element according to claim 1 , wherein
the wiring layer includes at least one layer with a reflective member, and
the reflective member overlaps with one of the first charge detection portion or the second charge detection portion in plan view.
3. The light-receiving element according to claim 1 , wherein
the wiring layer includes at least one layer with a light-shielding member, and
the light-shielding member overlaps with one of the first charge detection portion or the second charge detection portion in plan view.
4. The light-receiving element according to claim 1 , wherein
the first voltage application portion, the second voltage application portion, the first charge detection portion, and the second charge detection portion are on a same plane side of the semiconductor layer.
5. The light-receiving element according to claim 1 , wherein
the first voltage application portion and the second voltage application portion are configured to penetrate the semiconductor layer.
6. The light-receiving element according to claim 1 , wherein
the first voltage application portion and the second voltage application portion are on a plane side opposite to a surface of the semiconductor layer having the first charge detection portion and the second charge detection portion.
7. The light-receiving element according to claim 6 , wherein
the first voltage application portion is at a position where a center position of the first voltage application portion overlaps with the first charge detection portion in plan view, and
the second voltage application portion is at a position where a center position of the second voltage application portion overlaps with the second charge detection portion in plan view.
8. The light-receiving element according to claim 1 , wherein
each of the first voltage application portion and the second voltage application portion has a depth deeper than the first charge detection portion and the second charge detection portion.
9. The light-receiving element according to claim 1 , wherein
the first voltage application portion and the second voltage application portion include protruding portions formed on an upper surface above an interface of the semiconductor layer.
10. The light-receiving element according to claim 1 , wherein
planar shapes of the first voltage application portion, the second voltage application portion, the first charge detection portion, and the second charge detection portion are one of circular, rectangular, or triangular,
the first voltage application portion and the second voltage application portion are point-symmetrical with respect to a pixel center, and
the first charge detection portion and the second charge detection portion are point-symmetrical with respect to the pixel center.
11. The light-receiving element according to claim 1 , wherein
planar shapes of the first voltage application portion, the second voltage application portion, the first charge detection portion, and the second charge detection portion are either L-shaped or comb-shaped,
the first voltage application portion and the second voltage application portion faces each other,
the first charge detection portion and the second charge detection portion faces each other.
12. The light-receiving element according to claim 1 , wherein
a set of the first voltage application portion and the first charge detection portion having a rectangular planar shape, and a set of the second voltage application portion and the second charge detection portion having a rectangular planar shape are alternately arranged.
13. The light-receiving element according to claim 1 , wherein
the first voltage application portion having a rectangular planar shape and the first charge detection portion having a rectangular planar shape face each other in a diagonal direction of a pixel, and
the second voltage application portion having a rectangular planar shape and the second charge detection portion having a rectangular planar shape face each other in a diagonal direction different from the diagonal direction of the first voltage application portion and the first charge detection portion.
14. The light-receiving element according to claim 1 , wherein
the first voltage application portion having a triangular planar shape and the first charge detection portion having a triangular planar shape face each other in a first direction of a pixel, and
the second voltage application portion having a triangular planar shape and the second charge detection portion having a triangular planar shape face each other in a second direction orthogonal to the first direction.
15. The light-receiving element according to claim 1 , wherein
the first voltage application portion and the second voltage application portion comprise one of silicon, polysilicon, or a metal material.
16. The light-receiving element according to claim 1 , wherein
the first voltage application portion and the second voltage application portion are respectively configured by a first P-type semiconductor region and a second P-type semiconductor region in the semiconductor layer.
17. The light-receiving element according to claim 1 , wherein
the first voltage application portion and the second voltage application portion are respectively configured by first transfer transistor and second transfer transistor in the semiconductor layer.
18. A distance-measuring module, comprising:
a light-receiving element including:
an on-chip lens;
a wiring layer; and
a semiconductor layer between the on-chip lens and the wiring layer, the semiconductor layer including
a first voltage application portion configured to receive a first voltage,
a second voltage application portion configured to receive a second voltage different from the first voltage,
a first charge detection portion around the first voltage application portion, and
a second charge detection portion around the second voltage application portion,
an insulating film that covers each of the first voltage application portion and the second voltage application portion, and
a hole concentration strengthening layer on an outer periphery of the insulating film;
a light source configured to radiate irradiation light in which brightness periodically varies; and
a light-emission control unit configured to control irradiation timing of the irradiation light.