Semiconductor light-receiving element and manufacturing method of semiconductor light-receiving element
A semiconductor light-receiving element includes a substrate; a light-receiving mesa portion, formed on top of the substrate, including a first semiconductor layer of a first conductivity type, an absorption layer, and a second semiconductor layer of a second conductivity type; a light-receiving portion electrode, formed above the light-receiving mesa portion, connected to the first semiconductor layer; a pad electrode formed on top of the substrate; and a bridge electrode, placed so that an insulating gap is interposed between the bridge electrode and the second semiconductor layer, configured to connect the light-receiving portion electrode and the pad electrode on top of the substrate, the bridge electrode being formed in a layer separate from layers of the light-receiving portion electrode and the pad electrode.
1. A manufacturing method of a semiconductor light-receiving element comprising:
forming a light-receiving mesa portion on top of a substrate;
forming a light-receiving portion electrode above the light-receiving mesa portion;
forming a pad electrode on top of the substrate; and
forming a bridge electrode connecting the light-receiving portion electrode and the pad electrode,
wherein the forming the bridge electrode includes:
forming a resist that has, when viewed from above the substrate, an opening in a region in which the bridge electrode is to be formed and an overhang portion on an inner side surface of the opening;
forming a metal film on a top surface of the resist and in the region in which the bridge electrode is to be formed; and
removing the resist to remove a portion of the metal film that is formed on the top surface of the resist.
2. The manufacturing method of claim 1 , wherein a portion of the bridge electrode is formed in a layer below a portion of the pad electrode.
3. The manufacturing method of claim 1 , wherein the bridge electrode is formed in a layer above a layer of the light-receiving portion electrode and a layer of the pad electrode.
4. The manufacturing method of claim 1 , wherein the light-receiving portion electrode and the pad electrode are formed during a same period of time.
5. The manufacturing method of claim 1 , wherein the light-receiving portion electrode is formed during a first period of time; and
wherein the bridge electrode is formed during a second period of time.
6. The manufacturing method of claim 1 , wherein the metal film is formed by vapor deposition.
7. The manufacturing method of claim 1 , wherein the bridge electrode and the pad electrode are connected at a point closer to the pad electrode than to a region in which a contact layer of the light-receiving mesa portion is placed when viewed from above the substrate.
8. The manufacturing method of claim 7 , wherein the contact layer is an n-type contact layer.
9. The manufacturing method of claim 1 , further comprising:
forming a passivation film on a top surface of the light-receiving mesa portion; and
forming a through-hole in a region of the passivation film; and
wherein forming the light-receiving portion electrode comprises:
forming the light-receiving portion electrode in the through-hole.
10. The manufacturing method of claim 1 , wherein forming the light-receiving portion electrode comprises:
forming the light-receiving portion electrode using a resist application process, a metal film vaporization process, and a lift-off process.
11. The manufacturing method of claim 1 , wherein forming the pad electrode comprises:
forming the pad electrode using a resist application process, a metal film vaporization process, and a lift-off process.
12. A semiconductor light-receiving element comprising:
a light-receiving mesa portion formed on top of a substrate;
a light-receiving portion electrode formed above the light-receiving mesa portion;
a pad electrode formed on top of the substrate; and
a bridge electrode configured to connect the light-receiving portion electrode and the pad electrode on top of the substrate,
the bridge electrode being formed in a layer separate from layers of the light-receiving portion electrode and the pad electrode.
13. The semiconductor light-receiving element of claim 12 , wherein a portion of the bridge electrode is formed in a layer below a portion of the pad electrode.
14. The semiconductor light-receiving element of claim 12 , wherein the bridge electrode is formed in a layer above a layer of the light-receiving portion electrode and a layer of the pad electrode.
15. The semiconductor light-receiving element of claim 12 , wherein the bridge electrode and the pad electrode are connected at a point closer to the pad electrode than to a region in which a contact layer of the light-receiving mesa portion is placed when viewed from above the substrate.
16. The semiconductor light-receiving element of claim 15 , wherein the contact layer is an n-type contact layer.
17. The semiconductor light-receiving element of claim 12 , further comprising:
an insulating gap interposed between the bridge electrode and a layer of the light-receiving mesa portion.
18. The semiconductor light-receiving element of claim 12 , further comprising:
a passivation film on a top surface of the light-receiving mesa portion,
wherein the light-receiving portion electrode is formed in a through-hole of the passivation film.
19. The semiconductor light-receiving element of claim 12 , further comprising:
a pad mesa portion interposed between the substrate and the pad electrode.
20. The semiconductor light-receiving element of claim 12 , wherein the light-receiving portion electrode is connected to a semiconductor layer of the light-receiving mesa portion.