Bias control structure for avalanche photodiodes
According to some implementations, an avalanche photodiode may include a photon absorbing layer to absorb photons of an optical beam and to provide a response. The avalanche photodiode may include a gain response layer to provide a gain to the response. The avalanche photodiode may include a bias control structure connected to the gain response layer to control an electric field in the photon absorbing layer and the gain response layer.
1. An avalanche photodiode, comprising:
a photon absorbing layer to absorb photons of an optical beam and to provide a response;
a gain response layer to provide a gain to the response; and
a bias control structure connected to the gain response layer to control an electric field in the photon absorbing layer and the gain response layer.
2. The avalanche photodiode of claim 1 , wherein a top portion of the photon absorbing layer is p-doped to form an ohmic contact to receive an anode.
3. The avalanche photodiode of claim 1 , wherein a portion of the gain response layer is p-doped to form a charge medium.
4. The avalanche photodiode of claim 1 , wherein a gain value of the avalanche photodiode is optimized based on a first width of a charge region of the gain response layer and a second width of the photon absorbing layer.
5. The avalanche photodiode of claim 1 , wherein a portion of the gain response layer is n-doped to form an ohmic contact to receive a cathode.
6. The avalanche photodiode of claim 1 , wherein a portion of the gain response layer is p-doped to form an ohmic contact to receive the bias control structure.
7. A photodiode, comprising:
a substrate;
a buffer layer;
a silicon layer, comprising:
a set of p-doped silicon sections, comprising:
a first p-doped silicon section, and
a second p-doped silicon section,
a set of intrinsic silicon sections sandwiching the set of p-doped silicon sections, and
a set of n-doped silicon sections sandwiching the set of intrinsic silicon sections;
a set of germanium layers, comprising:
an intrinsic germanium layer disposed on the set of intrinsic silicon sections and the first p-doped silicon section, and
a p-doped germanium layer disposed on the intrinsic germanium layer;
a set of cathodes disposed on the set of n-doped silicon sections;
an anode disposed on the p-doped germanium layer; and
a bias control structure disposed on the second p-doped silicon section.
8. The photodiode of claim 7 , wherein the set of germanium layers is epitaxially grown on the silicon layer.
9. The photodiode of claim 7 , wherein a total thickness of the set of germanium layers is less than 800 nanometers (nm).
10. The photodiode of claim 7 , further comprising:
a spiral inductor connected to the bias control structure to isolate a radio frequency signal and a direct current signal.
11. The photodiode of claim 7 , further comprising:
a silicon waveguide coupled to the first p-doped silicon section.
12. The photodiode of claim 7 , wherein the anode is to provide a first negative voltage to the intrinsic germanium layer and the bias control structure is to apply a second negative voltage to control an electric field in the intrinsic germanium layer.
13. The photodiode of claim 7 , wherein the anode, the set of cathodes, and the bias control structure are to induce a first electric field in the intrinsic germanium layer and a second electric field in the set of intrinsic silicon sections.
14. The photodiode of claim 13 , wherein the second electric field is greater than the first electric field.
15. The photodiode of claim 7 , further comprising:
a cladding material to enclose the set of cathodes, the anode, the set of germanium layers, and the silicon layer.
16. An optical detector, comprising:
an avalanche photodiode, comprising:
a first layer to absorb photons of an optical beam and to provide a response;
a second layer to provide a gain to the response; and
a bias control structure connected to the first layer to control a first electric field in the first layer and a second electrical field in the second layer; and
a waveguide coupled to the avalanche photodiode to direct the optical beam to the second layer.
17. The optical detector of claim 16 , further comprising an anode and a cathode separate from the bias control structure.
18. The optical detector of claim 16 , wherein the first layer is germanium and the second layer is silicon.
19. The optical detector of claim 16 , wherein the optical detector is a III-V semiconductor optical detector.
20. The optical detector of claim 16 , wherein the avalanche photodiode further comprises:
a substrate,
wherein the substrate is indium-gallium-arsenide (InGaAs) or indium phosphide (InP).