Method for growing β phase of gallium oxide ([β]-Ga2O3) single crystals from the melt contained within a metal crucible

A method for growing beta phase of gallium oxide (β-Ga2O3) single crystals from a melt contained within a metal crucible, comprising the steps of:

• providing into a growth chamber a thermal system or growth furnace (100, 200, 300, 400, 500, 600) comprising the metal crucible (101, 201, 301, 401, 501, 601) containing the Ga2O3 starting material (102, 202, 302, 402, 502, 602), a thermal insulation (103, 203, 303, 403, 503, 603) surrounding the metal crucible (101, 201, 301, 401, 501, 601) and a heater (104, 204, 304, 404, 504, 604) disposed around the metal crucible (101, 201, 301, 401, 501, 601);
• providing or creating a crystal seed (105, 205, 305, 405, 505, 605) within the growth furnace (100, 200, 300, 400, 500, 600);
• introducing at least into the growth furnace (100, 200, 300, 400, 500, 600) a growth atmosphere (120, 220, 320, 420, 520, 620) containing oxygen;
• heating up the metal crucible (101, 201, 301, 401, 501, 601) by the heater (104, 204, 304, 404, 504, 604), which in turns heats up the Ga2O3 starting material (102, 202, 302, 402, 502, 602) until melting;
• contacting the crystal seed (105, 205, 305, 405, 505, 605) with the molten Ga2O3 starting material (102, 202, 302, 402, 502, 602) contained within the metal crucible (101, 201, 301, 401, 501, 601);
• growing a β-Ga2O3 single crystal (110, 210, 310, 410, 510, 610) on the crystal seed (105, 205, 305, 405, 505, 605) by temperature gradients between the crystal seed and the melt;
• cooling down the grown β-Ga2O3 single crystal (110, 210, 310, 410, 510, 610) to room temperature (RT) once the crystal growth step has been completed;
• characterized in that it further comprises the steps of:
• i) providing into the growth furnace (100, 200, 300, 400, 500, 600) the growth atmosphere (120, 220, 320, 420, 520, 620) consisting of a mixture of pure oxygen and at least one non-reducing gas selected from the group consisting of Ar, N2, He Xe, Ne, and CO2, with a variable oxygen concentration (OC) or partial pressure at substantially atmospheric pressure in such a way that the oxygen concentration (OC) reaches a growth oxygen concentration value (C2, C2′, C2″) in the concentration range (SC) of 5-100 vol. % below (8, 9) the melting temperature (MT) of Ga2O3 or at (6, 7) the melting temperature (MP) or after (5) complete melting of the Ga2O3 starting material (102, 202, 302, 402, 502, 602) adapted to minimize creation of metallic gallium amount (CR1, CR2, CR3) and thus eutectic formation with the metal crucible (101, 201, 301, 401, 501, 601) and to improve stoichiometry of the Ga2O3 starting material (102, 202, 302, 402, 502, 602) and crystal growth stability;
• and
• ii) maintaining the growth oxygen concentration value (C2, C2′, C2″) within the oxygen concentration range (SC) during the crystal growth step of the β-Ga2O3 single crystal (110, 210, 310, 410, 510, 610) from the melt at the growth temperature (GT).