Mutual compatibility of AlGaN HEMT and HTS (YBCO) technology

The possibility of the integration of a high-temperature superconductor thin film with active GaN devices at a working temperature of liquid nitrogen (77 K) are examined. We prepare YBa2Cu3O7−x (YBCO) films using a pulsed-laser deposition method on a hexagonal GaN of AlGaN/GaN substrate and next create circular high electron mobility transistor (C-HEMT) structures on the same substrate. The YBCO films with a maximum critical temperature of ≈80 K were grown on an MgO buffered hexagonal GaN substrate. The YBCO films were grown at the maximum heater temperature of 760 °C. Structural properties of the YBCO films are presented. We applied a special fullerene mask and bromoethyl alcohol to avoid a YBCO film and MgO buffer layer from part of the AlGaN/GaN substrate. This was used for the preparation of the C-HEMT devices. We show that the 2DEG channel of transistors is not degraded despite applying the high-temperature deposition processes of the superconducting films.