# US 12,765,080 B2 · Photodiode and method of fabricating a photodiode > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,765,080 B2 - Document ID: US12765080B2 - Status: Granted - Kind: B2 - Application number: 18/031,909 - Filed: 2021-10-14 - Published: 2023-11-16 - Granted: 2026-10-13 - Earliest claimed: 2020-10-16 - Assignees: Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. - Applicants: Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. - Inventors: Patrick Runge; Tobias Beckerwerth - Web page: https://patentgrep.com/patent/US12765080B2 ## CPC - H10F 30/223: the potential barrier being a PIN barrier - H10F 71/1272: {comprising at least three elements, e.g. GaAlAs or InGaAsP} - H10F 77/1248: {having three or more elements, e.g. GaAlAs, InGaAs or InGaAsP} - H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION ## Abstract Provided is a photodiode, including a substrate formed by a III-V semiconductor material. The substrate is made of InP; at least one light absorption layer; and at least one doped contact layer. The absorption layer is to be illuminated through the contact layer. The contact layer includes a semiconductor material having an indirect band gap and has a thickness of at least 200 nm. ## Claims ### Claim 1 A photodiode, comprising: a substrate formed by a III-V semiconductor material, wherein the substrate is made of InP; at least one light absorption layer; and at least one doped contact layer, wherein the absorption layer is to be illuminated through the contact layer, and wherein the contact layer comprises a semiconductor material having an indirect band gap and has a thickness of at least 200 nm. ### Claim 2 (depends on 1) The photodiode as claimed in claim 1, wherein the contact layer is p-doped. ### Claim 3 (depends on 1) The photodiode as claimed in claim 1, wherein the contact layer comprises a semiconductor material consisting of a composition that contains Al and/or Sb. ### Claim 4 (depends on 3) The photodiode as claimed in claim 3, wherein a content of Al is at least 0.42. ### Claim 5 (depends on 1) The photodiode as claimed in claim 1, wherein a lattice mismatch of the semiconductor material of the contact layer and the semiconductor material of the substrate does not exceed +/−750 ppm. ### Claim 6 (depends on 1) The photodiode as claimed in claim 1, wherein the absorption layer comprises InGaAs or GaAsSb. ### Claim 7 (depends on 6) The photodiode as claimed in claim 6, wherein the photodiode comprises at least two absorption layers, wherein wherein one of the absorption layers is adjacent the contact layer and/or is a GaAsSb layer. ### Claim 8 (depends on 1) The photodiode as claimed in claim 1, further comprising at least one partially depleted collector layer arranged on a side of the absorption layer facing towards an n-contact layer. ### Claim 9 (depends on 1) The photodiode as claimed in claim 1, further comprising a metal contact in electrical contact with the contact layer. ### Claim 10 (depends on 9) The photodiode as claimed in claim 9, wherein the metal contact is arranged directly on the contact layer or at least one semiconductor layer is arranged between the metal contact and the contact layer. ### Claim 11 (depends on 9) The photodiode as claimed in claim 9, wherein the metal contact covers only a part of the contact layer. ### Claim 12 (depends on 1) The photodiode as claimed in claim 1, wherein the contact layer is a first contact layer and the photodiode comprises a second contact layer doped complementary to the first contact layer and arranged on a side of the absorption layer facing away from the first contact layer. ### Claim 13 (depends on 12) The photodiode as claimed in claim 12, wherein a layer with a composition grading is arranged between two undepleted layers located between the first and the second contact layer. ### Claim 14 (depends on 12) The photodiode as claimed in claim 12, wherein also the second contact layer comprises a semiconductor material having an indirect band gap. ### Claim 15 A photodiode, comprising a substrate formed by a III-V semiconductor material, wherein the substrate is made of InP; at least one light absorption layer; at least one doped first contact layer, wherein the absorption layer is to be illuminated through the contact layer; a second contact layer doped complementary to the first contact layer and arranged on a side of the absorption layer facing away from the first contact layer; and at least one undoped and/or partially depleted collector layer arranged on the side of the absorption layer facing towards the second contact layer, wherein the first contact layer comprises a semiconductor material having an indirect band gap and has a thickness of at least 200 nm. ### Claim 16 (depends on 15) The photodiode as claimed in claim 15, wherein the collector layer is non-absorbing regarding an absorption wavelength of the absorption layer or has a lower absorption regarding the absorption wavelength of the absorption layer than the absorption layer. ### Claim 17 (depends on 16) The photodiode as claimed in claim 16, wherein the collector layer has a band gap having a band gap energy larger than an energy corresponding to the absorption wavelength of the absorption layer. ### Claim 18 (depends on 15) The photodiode as claimed in claim 15, further comprising an additional absorption layer arranged between the first contact layer and the light absorption layer. ### Claim 19 (depends on 15) The photodiode as claimed in claim 15, wherein the photodiode has a unique travelling carrier configuration. ### Claim 20 A method of fabricating a photodiode, comprising the steps of: providing a substrate formed by a III-V semiconductor material, wherein the substrate is made of InP; generating at least one light absorption layer on the substrate; and generating at least one doped contact layer on the substrate, wherein the absorption layer is to be illuminated through the contact layer, wherein the contact layer comprises a semiconductor material having an indirect band gap and has a thickness of at least 200 nm.