Photodetection device with matrix array of avalanche diodes
A photodetecting device includes a semiconductor substrate, a plurality of avalanche photodiodes each having a light receiving region, the avalanche photodiodes being arranged in a matrix at the semiconductor substrate, and a plurality of through-electrodes electrically connected to corresponding light receiving regions. The plurality of through-electrodes are arranged for each area surrounded by four mutually adjacent avalanche photodiodes of the plurality of avalanche photodiodes. Each of the light receiving regions has, when viewed from a direction perpendicular to a first principal surface of the semiconductor substrate, a polygonal shape including a pair of first sides opposing each other in a row direction and extending in a column direction and four second side opposing four through-electrodes surrounding the light receiving region and extending in directions intersecting with the row direction and the column direction. The length of the first side is shorter than the length of the second side.
1. A photodetecting device comprising:
a semiconductor substrate including a first principal surface and a second principal surface that oppose each other;
a plurality of avalanche photodiodes each including a light receiving region disposed at the first principal surface side of the semiconductor substrate, the avalanche photodiodes being
arranged in a matrix at the semiconductor substrate, and arranged to operate in Geiger mode; and
a plurality of through-electrodes electrically connected to corresponding light receiving regions, and penetrating through the semiconductor substrate in a thickness direction,
wherein the plurality of through-electrodes are arranged for each area surrounded by four mutually adjacent avalanche photodiodes of the plurality of avalanche photodiodes,
each of the light receiving regions has, when viewed from a direction perpendicular to the first principal surface, a polygonal shape including a pair of first sides opposing each other in a row direction and extending in a column direction and four second sides opposing four through-electrodes surrounding the light receiving region and extending in directions intersecting with the row direction and the column direction, and
a length of the first side is shorter than a length of the second side.
2. The photodetecting device according to claim 1 , wherein the polygonal shape of each of the light receiving regions further includes a pair of third sides opposing each other in the column direction and extending in the row direction, and
the length of the third side is shorter than the length of the second side.
3. The photodetecting device according to claim 1 , wherein a total length of the four second sides is equal to or more than 50% of an entire circumference of the light receiving region.
4. The photodetecting device according to claim 1 , wherein, when viewed from the direction perpendicular to the first principal surface, a groove is formed at the first principal surface side of the semiconductor substrate to surround the light receiving region.
5. The photodetecting device according to claim 4 , wherein when viewed from the direction perpendicular to the first principal surface, the groove surrounds an entire circumference of the corresponding light receiving region.
6. The photodetecting device according to claim 4 , wherein the groove formed to surround two light receiving regions adjacent to each other in the row direction shares a portion formed between the two light receiving regions adjacent to each other in the row direction.
7. The photodetecting device according to claim 4 , wherein the groove formed to surround two light receiving regions adjacent to each other in the column direction shares a portion formed between the two light receiving regions adjacent to each other in the column direction.
8. The photodetecting device according to claim 4 , wherein, when viewed from the direction perpendicular to the first principal surface, an area surrounded by the groove has a polygonal shape.
9. The photodetecting device according to claim 1 , wherein the through-electrode is arranged in a through-hole penetrating through the semiconductor substrate in the thickness direction,
when viewed from the direction perpendicular to the first principal surface, an opening of the through-hole has a circular shape, and
an insulating layer is arranged in an inner peripheral surface of the through-hole.