Photodiode having rounded edges for high electrostatic discharge threshold
View Patent ↗In one example, an optical detector includes a photosensitive layer, and a group of additional layers associated with that photosensitive layer. The group of additional layers may include first and second contact layer configured for electrical communication with the photosensitive layer. In this example, one of the group of layers is shaped so as to define a corner whose radius of curvature is greater than about 2 microns.
1. An optical detector, comprising:
a photosensitive layer;
a first contact layer; and
a second contact layer, the first and second contact layers being in electrical communication with the photosensitive layer, and one of the layers being shaped so as to define a corner whose radius of curvature is in the range of 5 microns to 20 microns resulting in a reduction in electric field strength below a desired level while maximizing overall size of the layer that is shaped so as to define the corner.
2. An optical subassembly comprising the optical detector as recited in claim 1 and a transmitter, wherein the optical detector comprises a monitor photodiode (“MPD”) configured and arranged to monitor the optical output power of the transmitter.
3. The optical detector as recited in claim 1 , wherein the layer that is shaped so as to define the corner comprises one of the contact layers.
4. The optical detector as recited in claim 1 , wherein the layer that is shaped so as to define the corner comprises the photosensitive layer.
5. The optical detector as recited in claim 1 , further comprising first and second surfaces, wherein the corner joins the first and second surfaces of the optical detector.
6. The optical detector as recited in claim 1 , further comprising first and second surfaces, wherein the corner joins the first and second surfaces of the optical detector.
7. An optical detector, comprising:
a photosensitive layer;
a first contact layer; and
a second contact layer, the first and second contact layers being in electrical communication with the photosensitive layer, and at least one of the layers having a substantially non-circular shape that is substantially free of linear portions and that includes a plurality of corners, none of which has a radius of curvature of less than two microns so as to maximize the overall size of the layer while reducing below a desired level an electrical field strength effect proximate to any corner of the at least one layer.
8. The optical detector as recited in claim 7 , wherein each of at least one of the corners is connected to first and second curved portions of the substantially non-circular shape.
9. The optical detector as recited in claim 7 , wherein each of at least one of the corners has a radius of curvature greater than 5 microns.
10. The optical detector as recited in claim 7 , wherein each of at least one of the corners defines a non-circular arc.
11. A method for manufacturing an optical detector, comprising:
producing a photosensitive layer;
producing a first contact layer;
producing a second contact layer, the first and second contact layers being in electrical communication with the photosensitive layer,
wherein at least one of the contact layers defines a substantially non-circular shape having a curvature at a corner, and
wherein the shape and magnitude of the curvature of the corner are determined based on a predetermined electrical field strength effect exhibited thereby.
12. The method according to claim 11 , wherein the radius of the curvature is at least five micron resulting in a reduction in electric field strength below the electrical field strength of a radius of curvature of about one or two micron.
13. A according to claim 11 , wherein the shape of the intersection is not entirely round so as to increase surface area of the photosensitive area while reducing the electrical field strength due to a lack of sharp corners.
14. The optical detector as recited in claim 11 , wherein the corner is connected to first and second curved portions of a substantially non-circular shape.
15. The optical detector as recited in claim 11 , wherein each of the intersecting layers has top and bottom surfaces but no appreciable side surfaces.