US 12,243,947 B2
Avalanche photodiode sensor and distance measuring device including concave-convex portions for reduced reflectance
Shinichiro Yagi, Osaka (JP); and Toshifumi Wakano, Kanagawa (JP)
Assigned to Sony Semiconductor Solutions Corporation, Kanagawa (JP)
Appl. No. 17/430,834
Filed by SONY SEMICONDUCTOR SOLUTIONS CORPORATION, Kanagawa (JP)
PCT Filed Feb. 6, 2020, PCT No. PCT/JP2020/004602
§ 371(c)(1), (2) Date Aug. 13, 2021,
PCT Pub. No. WO2020/170841, PCT Pub. Date Aug. 27, 2020.
Claims priority of application No. 2019-029912 (JP), filed on Feb. 21, 2019.
Prior Publication US 2022/0140156 A1, May 5, 2022
Int. Cl. H01L 31/02 (2006.01); G01S 7/481 (2006.01); G01S 7/4863 (2020.01); H01L 27/146 (2006.01); H01L 31/107 (2006.01)
CPC H01L 31/02027 (2013.01) [G01S 7/481 (2013.01); G01S 7/4863 (2013.01); H01L 27/14629 (2013.01); H01L 27/1463 (2013.01); H01L 27/14634 (2013.01); H01L 27/14643 (2013.01); H01L 31/107 (2013.01); H01L 27/14607 (2013.01); H01L 27/14636 (2013.01)] 20 Claims
OG exemplary drawing
 
1. An avalanche photodiode sensor, comprising:
a first semiconductor substrate; and
a second semiconductor substrate bonded to a first surface of the first semiconductor substrate,
wherein the first semiconductor substrate includes:
a plurality of photoelectric conversion portions arranged in a matrix;
an element separation portion for element-separating the plurality of photoelectric conversion portions from each other,
wherein the plurality of photoelectric conversion portions include a first photoelectric conversion portion,
wherein the element separation portion has a first element separation region and a second element separation region,
wherein the first photoelectric conversion portion is arranged between the first element separation region and the second element separation region,
wherein the first semiconductor substrate further includes a first plurality of concave-convex portions arranged on a second surface of the first semiconductor substrate opposite to the first surface of the first semiconductor substrate and arranged between the first element separation region and the second element separation region, and
wherein the second semiconductor substrate includes a reading circuit connected to each of the photoelectric conversion portions; and
a flattening film extending above and across the first plurality of concave-convex portions and the element separation portion,
wherein a trench is provided on the second surface of the first semiconductor substrate in at least a part of a region defined by the first and second element separation regions, and
wherein a second plurality of concave-convex portions are provided on a bottom surface of the trench.