# US 10,439,082 B2 · Photodetector with reduced dark current > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,439,082 B2 - Document ID: US10439082B2 - Status: Granted - Kind: B2 - Application number: 15/761,051 - Filed: 2016-09-15 - Published: 2018-09-27 - Granted: 2019-10-08 - Earliest claimed: 2015-09-16 - Assignees: Societe Francaise de Detecteurs Infrarouges-Sofradir - Applicants: SociéTé FrançAise De DéTecteurs Infrarouges—Sofradir - Inventors: Laurent Rubaldo; Nicolas Pere Laperne; Alexandre Kerlain; Alexandru Nedelcu - Web page: https://patentgrep.com/patent/US10439082B2 ## CPC - H10F 77/143: {comprising quantum structures} - H10F 30/21: the devices being sensitive to infrared, visible or ultraviolet radiation - H10F 30/2215: {the devices comprising active layers made of only Group III-V materials} - H10F 77/146: {Superlattices; Multiple quantum well structures} - H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION ## Abstract The photodetector includes a photon absorbing region formed by a first semiconductor material having a first bandgap energy value. It also includes a blocking region formed by at least second and third semiconductor materials configured to prevent the majority charge carriers from passing between the photon absorbing region and a contact region, the second semiconductor material presenting a second bandgap energy value higher than the first bandgap energy value to form a quantum well with the third semiconductor material. The blocking region is doped. ## Claims ### Claim 1 Photodetector, comprising: a photon absorbing region formed by a first semiconductor material having a first bandgap energy value, a contact region made from semiconductor material, a blocking region formed by (i) at least one layer of a second semiconductor material and at least two layers of a third semiconductor material or (ii) at least two layers of a second semiconductor material and at least one layer of a third semiconductor material, the second semiconductor material being configured to oppose flow of majority charge carriers between the photon absorbing region and the contact region, the second semiconductor material presenting a second bandgap energy value higher than the first bandgap energy value, the third semiconductor material having a third bandgap energy value different from the second bandgap energy value, wherein the blocking region is doped and wherein the layers of second and third semiconductor materials form at least one quantum well in the blocking region. ### Claim 2 (depends on 1) Photodetector according to claim 1, wherein a thickness of the layers of second semiconductor material is at least twice that of a thickness of the layers of third semiconductor material. ### Claim 3 (depends on 1) Photodetector according to claim 1, wherein the blocking region is configured to be devoid of mini-bands. ### Claim 4 (depends on 1) Photodetector according to claim 1, wherein the blocking region comprises at least one layer of a fourth semiconductor material presenting a fourth bandgap energy value higher than the first bandgap energy value and different from the second bandgap energy value and from the third bandgap energy value. ### Claim 5 (depends on 1) Photodetector according to claim 1, including a substrate comprising the photon absorbing region, the blocking region, the contact region and a support region, and wherein the support region is separated from the contact region by the photon absorbing region and the blocking region. ### Claim 6 (depends on 5) Photodetector according to claim 5, further comprising: an additional contact region and an additional blocking region arranged between the photon absorbing region and the additional contact region, the additional blocking region being configured to block the minority charge carriers between the photon absorbing region and the additional contact region. ### Claim 7 (depends on 6) Photodetector according to claim 6, wherein the additional contact region is located between the support region and the photon absorbing region. ### Claim 8 (depends on 6) Photodetector according to claim 6, wherein the additional blocking region comprises layers of a fifth semiconductor material and layers of a sixth semiconductor material respectively presenting fifth and sixth bandgap energy values, the fifth and/or sixth bandgap energy value being higher than the first bandgap energy value, the layers of fifth and sixth semiconductor materials form at least one quantum well in the additional blocking region. ### Claim 9 (depends on 1) Photodetector according to claim 1, wherein the first semiconductor material is identical to the third semiconductor material and/or to the fifth semiconductor material. ### Claim 10 (depends on 1) Photodetector according to claim 1, wherein the blocking region and/or the additional blocking region are doped over their whole thickness. ### Claim 11 (depends on 1) Photodetector according to claim 1, wherein the blocking region defines one or more potential well regions and several potential barrier regions and wherein the blocking region is doped only in one or more of said potential well regions. ### Claim 12 (depends on 1) Photodetector according to claim 1, wherein the blocking region defines one or more potential well regions and several potential barrier regions and wherein the blocking region is doped only outside the potential well region or regions. ### Claim 13 (depends on 1) Photodetector according to claim 1, wherein the blocking region comprises an alternation of layers of second semiconductor material and of third semiconductor material and wherein the layers of second semiconductor material are tensile stressed and the layers of third semiconductor material are compressive stressed. ### Claim 14 (depends on 1) Photodetector according to claim 1, wherein the blocking region comprises between 1 and 10 quantum wells. ### Claim 15 (depends on 1) Photodetector according to claim 1, wherein the blocking region is in direct contact with the photon absorbing region. ### Claim 16 (depends on 1) Photodetector according to claim 1, wherein the blocking region is in direct contact with the contact region. ### Claim 17 (depends on 1) Photodetector according to claim 1, wherein the blocking region is formed by at least one layer of the second semiconductor material and at least two layers of the third semiconductor material. ### Claim 18 (depends on 1) Photodetector according to claim 1, wherein the blocking region is formed by at least two layers of the second semiconductor material and at least one layer of the third semiconductor material.