Integrated optical filter and photodetector and methods of fabricating the same

Patent metadata

Field	Value
Publication number	US-2022123159-A1
Application number	US-202017073152-A
Country	US
Kind code	A1
Filing date	Oct 16, 2020
Priority date	Oct 16, 2020
Publication date	Apr 21, 2022
Grant date	—

Abstract

Integrated optical filter and photodetectors and methods of fabrication thereof are described herein according to the present disclosure. An example of an integrated optical filter and photodetector described herein includes a substrate, an insulator layer on the substrate, and a semiconductor layer on the insulator layer. An optical filter having a resonant cavity is formed in or on the semiconductor layer. The integrated optical filter and photodetector further includes two first metal fingers and a second metal finger interdigitated between the two first metal fingers on the semiconductor layer forming Schottky barriers. The first metal fingers are constructed from a different metal relative to the second metal finger.

First claim

1 . An integrated optical filter and photodetector comprising:
a substrate; an insulator layer on the substrate; a semiconductor layer on the insulator layer; an optical filter having a resonant cavity formed in or on the semiconductor layer; a first metal finger and a second metal finger on the semiconductor layer forming Schottky barriers, wherein the first metal finger is constructed from a different metal relative to the second metal finger.

2 . The integrated optical filter and photodetector of claim 1 , wherein the optical filter is a ring resonator.

3 . The integrated optical filter and photodetector of claim 2 , wherein the second metal finger is interdigitated between two of the first metal fingers and wherein the first and second metal fingers are formed on the ring resonator.

4 . The integrated optical filter and photodetector of claim 3 , wherein the first metal fingers and the second metal finger interdigitated between the two first metal fingers have a ground signal ground (GSG) pad configuration.

5 . The integrated optical filter and photodetector of claim 1 , wherein the first metal finger forms a Schottky barrier with the semiconductor layer having a hole barrier height between about 0.2 eV to about 0.4 eV and wherein the second metal finger forms a Schottky barrier with the semiconductor layer having an electron barrier height between about 0.2 eV to about 0.4 eV.

6 . The integrated optical filter and photodetector of claim 1 , wherein the first metal fingers is constructed from one or more of: copper, aluminum, platinum, palladium, or gold.

7 . The integrated optical filter and photodetector of claim 1 , wherein the second metal finger is constructed from one or more of: copper, aluminum, platinum, palladium, or gold.

8 . The integrated optical filter and photodetector of claim 1 , wherein the semiconductor layer is undoped.

9 . The integrated optical filter and photodetector of claim 1 , wherein the semiconductor layer, insulator layer, and substrate have a Silicon-on-Insulator (SOI) structure.

10 . The integrated optical filter and photodetector of claim 1 , wherein the semiconductor layer does not include a germanium layer formed in or on the semiconductor layer.

11 . The integrated optical filter and photodetector of claim 1 , wherein the first metal fingers have a thickness between about 10 nm to about 70 nm.

12 . The integrated optical filter and photodetector of claim 1 , wherein the first metal fingers have a width between about 300 nm to about 500 nm.

13 . The integrated optical filter and photodetector of claim 1 , wherein the first metal finger is spaced from the second metal finger between about 100 nm to about 1000 nm,

14 . A method of forming an integrated optical filter and photodetector, the method comprising:
providing a substrate, an insulator layer on the substrate, and a semiconductor layer on the insulator layer; forming an optical filter having a resonant cavity in or on the semiconductor layer; depositing a first metal finger and a second metal finger on the semiconductor layer forming Schottky barriers, wherein the first metal finger is constructed from a different metal relative to the second metal finger.

15 . The method of claim 13 , wherein forming an optical filter in or on the semiconductor layer comprises forming a ring resonator.

16 . The method of claim 14 , wherein depositing a first metal finger and a second metal finger further comprises depositing the second metal finger interdigitated between two first metal fingers on the ring resonator.

17 . An optical system comprising:
an optical receiver comprising:
a waveguide configured to receive a multi-wavelength optical signal;
an array of two or more integrated optical filter and photodetectors coupled to the waveguide, wherein a first integrated optical filter and photodetector is configured to filter a first wavelength of light from the multi-wavelength optical signal propagating through the waveguide and a second integrated optical filter and photodetector is configured to filter a second wavelength of light from the multi-wavelength optical signal propagating through the waveguide different from the first wavelength of light, and wherein each of the first and second integrated optical filter and photodetectors comprises:
a substrate;
an insulator layer on the substrate;
a semiconductor layer on the insulator layer;
an optical filter having a resonant cavity formed in or on the semiconductor layer;
two first metal fingers and a second metal finger interdigitated between the two first metal fingers on the semiconductor layer forming Schottky barriers, wherein the first metal fingers are constructed from a different metal relative to the second metal finger.

18 . The optical system of claim 17 , further comprising:
an optical transmitter coupled to the optical receiver via an optical fiber, the optical transmitter comprising:
a multi-wavelength optical source configured to emit the multi-wavelength optical signal;
a waveguide coupled to the multi-wavelength optical source and configured to receive the multi-wavelength optical signal from the multi-wavelength optical source; and
an array of two or more optical modulators coupled to the waveguide, wherein a first optical modulator is configured to filter and modulate data onto the first wavelength of light from the waveguide and a second optical modulator is configured to filter and modulate data onto the second wavelength of light from the waveguide, and wherein the first and second modulated wavelengths of light are multiplexed together back into the waveguide and transmitted to the optical receiver via the optical fiber.

19 . The optical system of claim 18 , wherein each of the optical filters and optical modulators are ring resonators.

20 . The optical system of claim 19 , wherein the optical receiver does not include respective waveguides coupling each of the ring resonators to the photodetectors of the integrated optical filter and photodetectors.

Assignees

• Hewlett Packard Entpr Dev Lp

Inventors

• Yuan Yuan
• Huang Zhihong
• Liang Di
• Zeng Xiaoge

Classifications

• H10F71/121

  The active layers comprising only Group IV materials · CPC title

• H10F39/107

  having multiple elements covered by H10F30/00 in a repetitive configuration, e.g. radiation detectors comprising photodiode arrays · CPC title

• H10F30/2275

  being a metal-semiconductor-metal [MSM] Schottky barrier · CPC title

• H10F77/1692

  the films including only Group IV materials · CPC title

• H10F77/413 Primary

  directly associated or integrated with the devices, e.g. back reflectors (directly associated or integrated with photovoltaic cells H10F77/42) · CPC title