# US 2019/0172706 A1 · Process of forming silicon nitride (sin) film and semiconductor device providing sin film > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0172706 A1 - Document ID: US20190172706A1 - Status: Published application - Kind: A1 - Application number: 16/210,773 - Filed: 2018-12-05 - Published: 2019-06-06 - Earliest claimed: 2017-12-06 - Assignees: Sumitomo Electric Industries, Ltd. - Applicants: Sumitomo Electric Industries, Ltd. - Inventors: Kazuhide SUMIYOSHI - Web page: https://patentgrep.com/patent/US20190172706A1 ## CPC - H10P 14/6334: {using decomposition or reaction of gaseous or vapour phase compounds, i.e. chemical vapour deposition (deposition by physical ablation of a target H10P14/6329)} - H10W 74/137: {the encapsulations being directly on the semiconductor body (H10W74/134 takes precedence)} - C23C 16/345: {Silicon nitride} - C23C 16/45523: {Pulsed gas flow or change of composition over time} - C23C 16/45557: {Pulsed pressure or control pressure} - H10D 30/015: {of FETs having heterojunction interface channels or heterojunction gate electrodes, e.g. HEMT} - H10D 30/4755: {having wide bandgap charge-carrier supplying layers, e.g. modulation doped HEMTs such as n-AlGaAs/GaAs HEMTs} - H10P 14/6682: {the compound being a silane, e.g. disilane, methylsilane or chlorosilane} - H10P 14/69433: {the material being a silicon nitride not containing oxygen, e.g. SixNy or SixByNz} - H10D 64/256: {for lateral devices wherein the source or drain electrodes are recessed in semiconductor bodies (source or drain electrodes of TFTs H10D30/673)} - H10W 74/43: comprising oxides, nitrides or carbides, e.g. ceramics or glasses - H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10 - H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10 - C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04) - H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES ## Abstract A sequence of a low pressure chemical vapor deposition (LPCVD) technique for nitride semiconductor materials is disclosed. The sequence comprises steps of: setting a temperature in a furnace to be 750 to 900° C.; substituting an atmosphere in the furnace to ammonia (NH3); depositing a SiN film at an initial pressure by supplying di-chloro-silane (SiH2Cl2); subsequently depositing the SiN film at a deposition pressure that is higher than the initial pressure. The sequence of the invention has a feature that the initial pressure is at least higher than 60% of the deposition pressure. ## Claims ### Claim 1 A process of depositing a silicon nitride (SiN) film on a nitride semiconductor layer by a low pressure chemical vapor deposition (LPCVD) technique, the process comprising steps of: setting a temperature in a LPCVD furnace to be higher than 750° C. but lower than 900° C.; substituting an atmosphere in the LPCVD furnace to an ammonia (NH3) atmosphere; setting a pressure in the LPCVD furnace to be a first pressure by flowing only ammonia (NH3); depositing the SiN film by supplying di-chloro-silane (SiH2Cl2) at the first pressure; and subsequently depositing the SiN film by changing the pressure to a second pressure that is higher than the first pressure, wherein the first pressure is 60% or more of the second pressure. ### Claim 2 (depends on 1) The process according to claim 1, wherein the first pressure is equal to or lower than the second pressure. ### Claim 3 (depends on 1) The process according to claim 1, wherein the step of depositing the SiN film at the first pressure deposits the SiN film by at least 2 nm. ### Claim 4 (depends on 1) The process according to claim 1, wherein the step of setting the temperature is carried out at a nitrogen (N2) atmosphere in the LPCVD furnace. ### Claim 5 (depends on 1) The process according to claim 1, wherein the step of substituting the atmosphere to the ammonia atmosphere includes steps of: evacuating the LPCVD furnace to a pressure lower than 1 Pa, and supplying ammonia (NH3) within the LPCVD furnace. ### Claim 6 (depends on 1) The process according to claim 1, wherein the step of depositing the SiN film includes a step of maintaining the pressure in the LPCVD furnace to be the first pressure as increasing the supply of di-chloro-silane (SiH2Cl2) concurrently with decrease of ammonia (NH3). ### Claim 7 (depends on 1) The process according to claim 1, wherein the steps of subsequently depositing the SiN film maintains the supply of ammonia (NH3) and di-chloro-silane (SiH2Cl2) substantially equal to the supply of NH3 and SiH2Cl2 at an end of the step of depositing the SiN film. ### Claim 8 (depends on 1) The process according to claim 1, wherein the SiN film has a composition ratio of silicon (Si) against nitrogen (N) equal to or greater than ¾. ### Claim 9 A process of forming a nitride semiconductor device comprising steps of: forming a semiconductor stack on a substrate, the semiconductor stack including nitride semiconductor layers; forming a passivation film made of silicon nitride (SiN) on the semiconductor stack by a low pressure chemical vapor deposition (LPCVD) technique; forming electrodes of a source and a drain on the semiconductor stack by forming respective openings in the passivation film; and forming an electrode of a gate on the semiconductor stack by forming an opening in the passivation film, wherein the step of forming the passivation film includes steps of: setting a temperature in a LPCVD furnace to be higher than 750° C. but lower than 900° C.; substituting an atmosphere in the LPCVD furnace to ammonia (NH3) atmosphere; setting a pressure in the LPCVD furnace to be a first pressure flowing only ammonia (NH3); depositing the SiN film by supplying di-chloro-silane (SiH2Cl2) at the first pressure; and subsequently depositing the SiN film by changing the pressure in a second pressure that is higher than the first pressure, wherein the first pressure is 60% or higher of the second pressure. ### Claim 10 (depends on 9) The process according to claim 9, wherein the first pressure is equal to or lower of the second pressure. ### Claim 11 (depends on 9) The process according to claim 9, wherein the step of depositing the SiN film at the first pressure deposits the SiN film by at least 2 urn. ### Claim 12 (depends on 9) The process according to claim 9, wherein the step of setting the temperature is carried out at a nitrogen (N2) atmosphere in the LPCVD furnace. ### Claim 13 (depends on 9) The process according to claim 9, wherein the step of substituting the atmosphere to the ammonia atmosphere includes steps of: evacuating the LPCVD furnace to a pressure lower than 1 Pa, and supplying ammonia (NH3) within the LPCVD furnace. ### Claim 14 (depends on 9) The process according to claim 9, wherein the step of depositing the SiN film includes a step of maintaining the pressure in the LPCVD furnace to be the first pressure as increasing the supply of di-chloro-silane (SiH2Cl2) concurrently with decrease of ammonia (NH3). ### Claim 15 (depends on 9) The process according to claim 9, wherein the steps of subsequently depositing the SiN film maintains the supply of ammonia (NH3) and di-chloro-silane (SiH2Cl2) substantially equal to the supply of NH3 and SiH2Cl2 at an end of the step of depositing the SiN film. ### Claim 16 (depends on 9) The process according to claim 9, wherein the SiN film has a composition ratio of silicon (Si) against nitrogen (N) equal to or greater than ¾.