Light reception element and method for manufacturing light-reception element
A light reception element includes a semiconductor portion having a first surface including a light receiving portion and a light shielding portion, and a light shielding metal film provided on the light shielding portion. The metal film has a second surface facing a side opposite to the first surface and receiving incident light. A plurality of recess portions are formed on the second surface. An inner surface of the recess portion includes a curved portion curved such that the recess portion reduces in size in a direction along the second surface from the second surface toward a bottom part of the recess portion.
1. A light reception element comprising:
a semiconductor portion having a first surface including a light receiving portion and a light shielding portion; and
a metal film for light shielding provided on the light shielding portion,
wherein the metal film has a second surface facing a side opposite to the first surface and receiving incident light,
wherein a plurality of recess portions are formed on the second surface,
wherein an inner surface of the recess portion includes a curved portion curved such that the recess portion reduces in size in a direction along the second surface from the second surface toward a bottom part of the recess portion, and
wherein the second surface includes a flat region provided around the recess portions.
2. The light reception element according to claim 1 ,
wherein the curved portion extends so as to form the bottom part.
3. The light reception element according to claim 2 ,
wherein a size of the recess portion in the second surface is equal to or smaller than a size of the metal film in a direction intersecting the second surface.
4. The light reception element according to claim 1 ,
wherein the recess portions are arranged at a constant pitch along the second surface.
5. A method for manufacturing a light reception element comprising:
a first step of forming a metal film for light shielding on a part of a first surface of a semiconductor portion to form a light receiving portion exposed from the metal film and a light shielding portion covered with the metal film on a first surface; and
a second step of performing isotropic etching on a second surface of the metal film facing a side opposite to the first surface to form a plurality of recess portions on a second surface by performing isotropic etching on the second surface of the metal film facing a side opposite to the first surface.
6. The method for manufacturing a light reception element according to claim 5 ,
wherein the isotropic etching is wet etching.