# US 2013/0153967 A1 · Compound Semiconductor Device with Buried Field Plate > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0153967 A1 - Document ID: US20130153967A1 - Status: Published application - Kind: A1 - Application number: 13/331,970 - Filed: 2011-12-20 - Published: 2013-06-20 - Earliest claimed: 2011-12-20 - Assignees: Infineon Technologies Austria AG - Inventors: Gilberto Curatola; Oliver Häberlen - Web page: https://patentgrep.com/patent/US20130153967A1 ## CPC - H10D 30/4755: {having wide bandgap charge-carrier supplying layers, e.g. modulation doped HEMTs such as n-AlGaAs/GaAs HEMTs} - H10D 30/015: {of FETs having heterojunction interface channels or heterojunction gate electrodes, e.g. HEMT} - H10D 62/126: {Top-view geometrical layouts of the regions or the junctions} - H10D 62/149: {Source or drain regions of field-effect devices} - H10D 62/357: {of FETs} - H10D 62/824: comprising only Group III-V materials heterojunctions, e.g. GaN/AlGaN heterojunctions - H10D 62/8503: {Nitride Group III-V materials, e.g. AlN or GaN} - H10D 64/01: Manufacture or treatment - H10D 64/111: {Field plates} - H10D 64/112: {comprising multiple field plate segments} - H10D 64/117: {Recessed field plates, e.g. trench field plates or buried field plates} - H10D 64/251: {Source or drain electrodes for field-effect devices} - H10D 64/411: {for FETs} - H10D 62/117: {Shapes of semiconductor bodies} - H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES ## Abstract A semiconductor device includes a first compound semiconductor material and a second compound semiconductor material on the first compound semiconductor material. The second compound semiconductor material comprises a different material than the first compound semiconductor material such that the first compound semiconductor material has a two-dimensional electron gas (2DEG). The semiconductor device further includes a buried field plate disposed in the first compound semiconductor material and electrically connected to a terminal of the semiconductor device. The 2DEG is interposed between the buried field plate and the second compound semiconductor material. ## Claims ### Claim 1 A semiconductor device, comprising: a first compound semiconductor material; a second compound semiconductor material on the first compound semiconductor material, the second compound semiconductor material comprising a different material than the first compound semiconductor material such that the first compound semiconductor material has a two-dimensional electron gas (2DEG); and a buried field plate disposed in the first compound semiconductor material and electrically connected to a terminal of the semiconductor device, the 2DEG being interposed between the buried field plate and the second compound semiconductor material. ### Claim 2 (depends on 1) The semiconductor device according to claim 1, wherein the buried field plate comprises the same material as the second compound semiconductor material. ### Claim 3 (depends on 2) The semiconductor device according to claim 2, wherein the buried field plate and the second compound semiconductor material each comprise AlGaN. ### Claim 4 (depends on 1) The semiconductor device according to claim 1, wherein the buried field plate comprises InGaN. ### Claim 5 (depends on 1) The semiconductor device according to claim 1, wherein the buried field plate comprises a more highly doped region of the first compound semiconductor material surrounded by a less highly doped region of the first compound semiconductor material. ### Claim 6 (depends on 1) The semiconductor device according to claim 1, further comprising: a gate region over the 2DEG; a source region extending through the second compound semiconductor material to the first compound semiconductor material and in contact with the buried field plate; and a drain region extending through the second compound semiconductor material to the first compound semiconductor material and spaced apart from the source region and the buried field plate. ### Claim 7 (depends on 6) The semiconductor device according to claim 6, wherein a distance between the buried field plate and the 2DEG is greater than a distance between the gate region and the 2DEG. ### Claim 8 (depends on 6) The semiconductor device according to claim 6, wherein the buried field plate extends laterally from the source region toward the drain region further than the gate region. ### Claim 9 (depends on 6) The semiconductor device according to claim 6, wherein the buried field plate and the source region comprise doped regions of the same doping type. ### Claim 10 (depends on 6) The semiconductor device according to claim 6, further comprising at least one additional buried field plate disposed in the first compound semiconductor material below the 2DEG and in contact with the source region, adjacent ones of the buried field plates being spaced apart from one another by a region of the first compound semiconductor material. ### Claim 11 (depends on 10) The semiconductor device according to claim 10, wherein the source region extends deeper into the first compound semiconductor material than the drain region. ### Claim 12 (depends on 10) The semiconductor device according to claim 10, wherein a second one of the buried field plates is spaced further away from the second compound semiconductor material than a first one of the buried field plates, and laterally extends further from the source region toward the drain region than the first one of the buried field plates. ### Claim 13 (depends on 6) The semiconductor device according to claim 6, wherein a distance between the buried field plate and the 2DEG increases in a direction laterally extending from the source region to the drain region. ### Claim 14 (depends on 1) The semiconductor device according to claim 1, further comprising a second 2DEG in the first compound semiconductor material and spaced further apart from the second compound semiconductor material than the first 2DEG, and wherein the buried field plate is interposed between the first and second 2DEGs. ### Claim 15 (depends on 14) The semiconductor device according to claim 14, wherein the first 2DEG extends laterally from a source region of the semiconductor device to a drain region of the semiconductor device and forms a channel of the semiconductor device, and the second 2DEG extends laterally from the source region toward the drain region and terminates before reaching the drain region. ### Claim 16 (depends on 1) The semiconductor device according to claim 1, further comprising a two-dimensional hole gas (2DHG) in the first compound semiconductor material and spaced further apart from the second compound semiconductor material than the 2DEG, and wherein the buried field plate is interposed between the 2DEG and the 2DHG. ### Claim 17 A semiconductor device, comprising: a first III-V semiconductor material; a second III-V semiconductor material on the first III-V semiconductor material, the second III-V semiconductor material comprising a different material than the first III-V semiconductor material such that the first III-V semiconductor material has a two-dimensional electron gas (2DEG); a gate region on the second III-V semiconductor material with the second III-V semiconductor material interposed between the 2DEG and the gate region; a source region extending through the second III-V semiconductor material to the first III-V semiconductor material; a drain region extending through the second III-V semiconductor material to the first III-V semiconductor material and spaced apart from the source region; and a metallization on a side of the first III-V semiconductor material facing away from the second III-V semiconductor material, the first III-V semiconductor material having a thickness which increases in a direction extending laterally from the source region to the drain region. ### Claim 18 (depends on 17) The semiconductor device according to claim 17, wherein the thickness of the first III-V semiconductor material increases stepwise in the direction extending laterally from the source region to the drain region. ### Claim 19 A method of manufacturing a semiconductor device, comprising: forming a first compound semiconductor material on a semiconductor substrate; forming a second compound semiconductor material on the first compound semiconductor material, the second compound semiconductor material comprising a different material than the first compound semiconductor material such that the first compound semiconductor material has a two-dimensional electron gas (2DEG); forming a buried field plate in the first compound semiconductor material so that the 2DEG is interposed between the buried field plate and the second compound semiconductor material; and electrically connecting the buried field plate to a terminal of the semiconductor device. ### Claim 20 (depends on 19) The method according to claim 19, wherein forming the buried field plate in the first compound semiconductor material comprises: forming a mask on the first compound semiconductor material prior to forming the second compound semiconductor material so that part of the first compound semiconductor material is exposed; implanting a dopant species into the first compound semiconductor material to form a concentration of the dopant species at a depth in the first compound semiconductor material; forming the second compound semiconductor material on the first compound semiconductor material after implantation of the dopant species, with the 2DEG interposed between the concentration of dopant species and the second compound semiconductor material; and annealing the semiconductor device to activate the dopant species and form the buried field plate. ### Claim 21 (depends on 19) The method according to claim 19, wherein forming the buried field plate in the first compound semiconductor material comprises: forming a mask above the second compound semiconductor material so that part of the second compound semiconductor material is uncovered by the mask; implanting a dopant species through the uncovered part of the second compound semiconductor material and into the first compound semiconductor material to form a concentration of the dopant species at a depth in the first compound semiconductor material, with the 2DEG interposed between the concentration of dopant species and the second compound semiconductor material; and annealing the semiconductor device to activate the dopant species and form the buried field plate. ### Claim 22 (depends on 19) The method according to claim 19, comprising forming the buried field plate of the same material as the second compound semiconductor material so that a second 2DEG arises in the first compound semiconductor material which is spaced further apart from the second compound semiconductor material than the first 2DEG, the buried field plate being interposed between the first and second 2DEGs. ### Claim 23 (depends on 19) The method according to claim 19, comprising forming the buried field plate of a different compound semiconductor material than the first and second compound semiconductor materials so that a two-dimensional hole gas (2DHG) arises in the first compound semiconductor material which is spaced further apart from the second compound semiconductor material than the 2DEG, the buried field plate being interposed between the 2DEG and the 2DHG. ### Claim 24 (depends on 19) The method according to claim 19, wherein forming the buried field plate in the first compound semiconductor material comprises: implanting a dopant species through a side of the first compound semiconductor material facing away from the second compound semiconductor material to form a concentration of the dopant species at a depth in the first compound semiconductor material; and annealing the semiconductor device to activate the dopant species and form the buried field plate. ### Claim 25 (depends on 19) The method according to claim 19, further comprising forming at least one additional buried field plate in the first compound semiconductor material below the 2DEG and in contact with the terminal of the semiconductor device, adjacent ones of the buried field plates being spaced apart from one another by a region of the first compound semiconductor material. ### Claim 26 (depends on 19) The method according to claim 19, wherein the terminal electrically connected to the buried field plate is formed by: removing at least a portion of the second compound semiconductor in a region of the semiconductor device; implanting a dopant species into the first compound semiconductor material in the region where at least a portion of the second compound semiconductor was removed; and annealing the semiconductor device to activate the dopant species and form the terminal. ### Claim 27 (depends on 19) The method according to claim 19, wherein the terminal electrically connected to the buried field plate is formed by: etching a recess through the second compound semiconductor material into the first compound semiconductor material; and filling the recess with an electrically conductive material so that a side of the buried field plate contacts the electrically conductive material.