# US 2021/0242021 A1 · Method of Making a Silicon Carbide Electronic Device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0242021 A1 - Document ID: US20210242021A1 - Status: Published application - Kind: A1 - Application number: 17/166,181 - Filed: 2021-02-03 - Published: 2021-08-05 - Earliest claimed: 2020-02-03 - Assignees: Hitachi Energy Switzerland AG - Applicants: ABB Power Grids Switzerland AG - Inventors: Giovanni Alfieri; Vinoth Sundaramoorthy - Web page: https://patentgrep.com/patent/US20210242021A1 ## CPC - H10P 30/21: {of electrically active species} - H10D 62/8325: {Silicon carbide} - H10D 64/0115: {to silicon carbide} - H10D 64/62: Electrodes ohmically coupled to a semiconductor - H10P 30/2042: {into crystalline silicon carbide} - H10P 30/218: {characterised by the implantation in a compound semiconductor of both electrically active and inactive species in the same semiconductor region to be doped n-type or p-type} - H10P 32/1204: {from a plasma phase} - H10D 8/50: PIN diodes - H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10 - H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES ## Abstract A method for forming a semiconductor device includes implanting first ions and second ions into a p-type silicon carbide layer from a first main side to form an implantation layer at the first main side. The implanting is performed by plasma immersion ion implantation in which the p-type silicon carbide layer is immersed in a plasma comprising the first ions and the second ions. The first ions can be ionized aluminum atoms and the second ions are different from the first ions. ## Claims ### Claim 1 A method for forming a semiconductor device, the method comprising: implanting first ions and second ions into a p-type silicon carbide layer from a first main side to form an implantation layer at the first main side, the implanting being performed by plasma immersion ion implantation in which the p-type silicon carbide layer is immersed in a plasma comprising the first ions and the second ions, the first ions being ionized aluminum atoms and the second ions being different from the first ions. ### Claim 2 (depends on 1) The method according to claim 1, wherein implanting the first and second ions into the p-type silicon carbide layer comprises: positioning the p-type silicon carbide layer in an enclosing chamber; generating the plasma from a source comprising aluminum; and then, independently from generating the plasma, applying a negative voltage between the p-type silicon carbide layer and a ground potential to accelerate the first ions and the second ions in the plasma towards the p-type silicon carbide layer from the plasma surrounding the p-type silicon carbide layer at an ion energy sufficient to implant the first ions and the second ions into the p-type silicon carbide layer. ### Claim 3 (depends on 2) The method according to claim 2, wherein the source comprises a gas comprising aluminum and carbon. ### Claim 4 (depends on 3) The method according to claim 3, wherein the gas comprises trimethylaluminum, triethylaluminum, tri-1-butylaluminum or trimethyl(tri-sec-butoxy)aluminum. ### Claim 5 (depends on 2) The method according to claim 2, wherein the accelerated ions hit onto the first main side with an energy of less than 10 keV. ### Claim 6 (depends on 1) The method according to claim 1, wherein the second ions comprise carbon or hydrogen. ### Claim 7 (depends on 6) The method according to claim 6, wherein a concentration of the carbon or hydrogen in the plasma is the same or higher than a concentration of aluminum in the plasma. ### Claim 8 (depends on 6) The method according to claim 6, wherein the plasma comprises nitrogen and chlorine and wherein a concentration of the nitrogen in the plasma is 10% or less of a concentration of aluminum in the plasma and a concentration of chlorine in the plasma is less than the concentration of aluminum in the plasma. ### Claim 9 (depends on 1) The method according to claim 1, wherein the implantation layer is formed having an aluminum concentration of at least 1·1018 cm−3. ### Claim 10 (depends on 1) The method according to claim 1, wherein further comprising performing additional steps to form a power semiconductor device, the power semiconductor device being a p-i-n diode, a Schottky diode, a junction barrier Schottky diode, an insulated gate bipolar transistor, a bipolar junction transistor or a thyristor. ### Claim 11 A method for forming a semiconductor device, the method comprising: implanting first ions and second ions into a p-type silicon carbide layer to form an implantation layer at a first main side, the implanting being performed by plasma immersion ion implantation in which the p-type silicon carbide layer is immersed in a plasma comprising the first ions and the second ions, the first ions being ionized aluminum atoms and the second ions being different from the first ions; and forming a metal layer on the first main side in contact with the implantation layer. ### Claim 12 (depends on 11) The method according to claim 11, wherein during and after implanting the first and second ions and before forming the metal layer a temperature of the p-type silicon carbide layer is kept below 1300° C. ### Claim 13 (depends on 11) The method according to claim 11, wherein during and after implanting the first and second ions and before forming the metal layer a temperature of the p-type silicon carbide layer is kept below 1000° C. ### Claim 14 (depends on 13) The method according to claim 13, wherein the temperature of the p-type silicon carbide layer is kept below 500° during the implanting and wherein the temperature of the p-type silicon carbide layer is kept below 800° C. after the metal layer forming step. ### Claim 15 (depends on 13) The method according to claim 13, wherein the temperature of the p-type silicon carbide layer is kept below 100° during the implanting and wherein the temperature of the p-type silicon carbide layer is kept below 100° C. after the metal layer forming step. ### Claim 16 (depends on 11) The method according to claim 11, wherein the metal layer is void of aluminum, titanium and nickel. ### Claim 17 (depends on 11) The method according to claim 11, wherein the metal layer comprises aluminum, titanium and nickel and wherein a concentration of aluminum in the metal layer is less than 1·1013 cm−3, a concentration of titanium in the metal layer is less than 2·1011 cm−3 and a concentration of nickel in the metal layer is less than 1·1011 cm−3. ### Claim 18 A method for forming a semiconductor device, the method comprising: positioning a p-type silicon carbide layer in an enclosing chamber; generating a plasma from a source comprising aluminum; and applying a negative voltage between the p-type silicon carbide layer and a ground potential to accelerate first ions and second ions in the plasma towards the p-type silicon carbide layer from the plasma surrounding the p-type silicon carbide layer at an ion energy sufficient to implant the first ions and the second ions into the p-type silicon carbide layer, the first ions being ionized aluminum atoms and the second ions being different from the first ions. ### Claim 19 (depends on 18) The method according to claim 18, wherein the source comprises a gas comprising trimethylaluminum, triethylaluminum, tri-1-butylaluminum or trimethyl(tri-sec-butoxy)aluminum. ### Claim 20 (depends on 18) The method according to claim 18, wherein the accelerated ions hit onto the p-type silicon carbide layer with an energy of less than 10 keV. ### Claim 21 (depends on 18) The method according to claim 18, wherein the second ions comprise carbon or hydrogen. ### Claim 22 (depends on 18) The method according to claim 18, wherein the plasma comprises nitrogen and chlorine and wherein a concentration of the nitrogen in the plasma is less than or equal to 10% of a concentration of aluminum in the plasma and a concentration of chlorine in the plasma is less than the concentration of aluminum in the plasma. ### Claim 23 (depends on 18) The method according to claim 18, wherein a temperature of the p-type silicon carbide layer is kept below 1000° C. while the negative voltage is being applied between the p-type silicon carbide layer and a ground potential.