# US 2021/0280424 A1 · Method for manufacturing a sic electronic device with reduced handling steps, and sic electronic device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0280424 A1 - Document ID: US20210280424A1 - Status: Published application - Kind: A1 - Application number: 17/190,722 - Filed: 2021-03-03 - Published: 2021-09-09 - Earliest claimed: 2020-03-05 - Assignees: STMicroelectronics S.r.l. - Applicants: STMicroelectronics S.r.l. - Inventors: Simone RASCUNA'; Paolo BADALA'; Anna BASSI; Mario Giuseppe SAGGIO; Giovanni FRANCO - Web page: https://patentgrep.com/patent/US20210280424A1 ## CPC - H10D 64/0115: {to silicon carbide} - H10D 8/051: {of Schottky diodes} - H10D 8/60: Schottky-barrier diodes - H10D 62/8325: {Silicon carbide} - H10D 64/0123: {to silicon carbide} - H10D 64/62: Electrodes ohmically coupled to a semiconductor - H10D 64/64: Electrodes comprising a Schottky barrier to a semiconductor - H10D 62/106: {having supplementary regions doped oppositely to or in rectifying contact with regions of the semiconductor bodies, e.g. guard rings with PN or Schottky junctions} - H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES ## Abstract A method for manufacturing an electronic device based on SiC includes forming a structural layer of SiC on a front side of a substrate. The substrate has a back side that is opposite to the front side along a direction. Active regions of the electronic device are formed in the structure layer, and the active regions are configured to generate or conduct electric current during the use of the electronic device. A first electric terminal is formed on the structure layer, and an intermediate layer is formed at the back side of the substrate. The intermediate layer is heated by a LASER beam in order to generate local heating such as to favor the formation of an ohmic contact of Titanium compounds. A second electric terminal of the electronic device is formed on the intermediate layer. ## Claims ### Claim 1 A method for manufacturing an electronic device based on SiC, comprising: forming, at a front side of a silicon carbide (SiC) substrate, a structural layer of SiC, the substrate having a back side opposite to the front side along a direction; forming, in said structural layer, active regions of said electronic device, said active regions having configured to generate or conduct electric current during the use of the electronic device; forming, on said structural layer, a first electric terminal; forming, an intermediate layer of a first metal at the back side of the substrate and subsequent to the forming the first electric terminal, the first metal including at least one of Titanium, Molybdenum, Tantalum, Tungsten, Cobalt, or Nickel; heating selective portions of said intermediate layer by a LASER beam to generate local heating of said selective portions at a temperature in a range 1400° C.-2600° C., so as to favor a formation of compounds of said first metal at said selective portions; and forming, on said intermediate layer a second electric terminal of said electronic device, subsequent to the heating selective portions of said intermediate layer. ### Claim 2 (depends on 1) The method according to claim 1, wherein said first metal is Titanium and said compounds of the first metal include TixCy, TixSiy and TixSiyCz. ### Claim 3 (depends on 2) The method according to claim 2, wherein said LASER beam is generated with the following parameters: wavelength in a range of 290 nm-370 nm; pulse duration in a range of 100-300 ns; number of pulses in a range of 1-10; and energy density in a range of 1-4 J/cm2. ### Claim 4 (depends on 3) The method according to claim 3, wherein said LASER beam is generated with the following parameters: wavelength substantially equal to 310 nm; pulse duration substantially equal to 160 ns; number of pulses substantially equal to 4; and energy density substantially equal to 3 J/cm2. ### Claim 5 (depends on 1) The method according to claim 1, wherein the formation of the compounds of the first metal occurs for an entire thickness, along said direction, of the intermediate layer. ### Claim 6 (depends on 1) The method according to claim 1, further comprising, prior to the forming the intermediate layer, thinning the substrate at the back side to a final thickness of the substrate equal to or less than 180 μm. ### Claim 7 (depends on 1) The method according to claim 1, wherein the substrate is one of: 4H—SiC, 6H—SiC, 3C—SiC, 15R—SiC. ### Claim 8 (depends on 1) The method according to claim 1, wherein said electronic device is one of: a Merged-PN-Schottky diode, Schottky Diodes, JBS Diodes, MOSFETs, IGBTs, JFETs, or DMOS. ### Claim 9 (depends on 8) The method according to claim 8, wherein said electronic device is a Merged-PN-Schottky (MPS) diode and wherein: the structural layer is a drift layer of the MPS diode having a first conductivity; the active regions include a doped region having a second conductivity opposite to the first conductivity; the first electric terminal is an anode metal terminal in electrical contact with the doped region and in direct electrical contact with the drift layer laterally to the doped region, so as to form a junction-barrier (JB) diode with said doped region and a Schottky diode with the drift layer; and the second electric terminal is a cathode terminal, wherein said JB diode and Schottky diode define an active area of the MPS diode. ### Claim 10 (depends on 9) The method according to claim 9, further comprising: depositing a second metal at said doped region; and carrying out a thermal annealing to enable the formation of a silicide of said second metal, thus forming an ohmic contact at the doped region. ### Claim 11 An electronic device, comprising: a substrate of silicon carbide (SiC), the substrate having a front side and a back side opposite to each other along a direction; a structural layer of SiC extending at the front side of the substrate; active regions extending in said structural layer, the active regions configured to generate or conduct electric current during the use of the electronic device; a first electric terminal extending on said structural layer; an intermediate layer of compounds of a first metal at the back side of the substrate, the first metal including at least one of Titanium, Molybdenum, Tantalum, Tungsten, or Cobalt; and a second electric terminal extending on the intermediate layer. ### Claim 12 (depends on 11) The device according to claim 11, wherein the intermediate layer includes Titanium and said compounds of the first metal include TixCy, TixSiy and TixSiyCz. ### Claim 13 (depends on 11) The device according to claim 11, wherein the substrate has a thickness equal to or less than 180 μm. ### Claim 14 (depends on 11) The device according to claim 11, wherein the substrate is one of: 4H—SiC, 6H—SiC, 3C—SiC, 15R—SiC. ### Claim 15 (depends on 11) The device according to claim 11, wherein said electronic device is one of: a Merged-PN-Schottky diode, Schottky Diodes, JBS Diodes, MOSFETs, IGBTs, JFETs, or DMOS. ### Claim 16 (depends on 15) The device according to claim 15, wherein said electronic device is a Merged-PN-Schottky (MPS) diode and wherein: the structural layer is a drift layer of the MPS diode having a first conductivity; the active regions include a doped region having a second conductivity opposite to the first conductivity; the first electric terminal is an anode terminal and the first metallization is in electrical contact with the doped region and in direct electrical contact with the drift layer laterally to the doped region, so as to form a junction-barrier (JB) diode with said doped region and a Schottky diode with the drift layer; and the second electric terminal is a cathode terminal, wherein the JB diode and the Schottky diode define an active area of the MPS diode. ### Claim 17 A system for manufacturing an electronic device, comprising: a first reaction chamber for the formation of a structural layer of silicon carbide (SiC) at a front side of a substrate of SiC; a second reaction chamber for the formation of active regions in said structural layer, said active regions configured to generate or conduct electric current during the use of the electronic device; a third reaction chamber for the formation of a first electric terminal on said structural layer and of an intermediate layer of a metal at the back side of the substrate, the metal including at least one of Titanium, Molybdenum, Tantalum, Tungsten, or Cobalt; and a LASER device, configured to generate a LASER beam dirigible towards selective portions of the intermediate layer so as to heat said selective portions in order to generate local heating at a temperature in a range 1400° C.-2600° C., favoring a formation of compounds of said metal at the selective portions. ### Claim 18 (depends on 17) The system according to claim 17, wherein said LASER device is configured to generate the LASER beam with the following parameters: wavelength in a range of 290 nm-370 nm; pulse duration in a range of 100 ns-300 ns; number of pulses in a range of 1-10; and energy density in a range of 1-4 J/cm2. ### Claim 19 (depends on 18) The system according to claim 18, wherein the LASER device is configured to at least partially melt the intermediate layer. ### Claim 20 (depends on 18) The system according to claim 18, wherein the substrate is one of: 4H—SiC, 6H—SiC, 3C—SiC, 15R—SiC.