Superconducting MgB2 thin films on silicon carbide substrates by hybrid physical–chemical vapor deposition

Abstract

We have used two polytypes of silicon carbide single crystals, 4H-SiC and 6H-SiC, as the substrates for MgB2 thin films grown by hybrid physical-chemical vapor deposition (HPCVD). The c-cut surface of both polytypes has a hexagonal lattice that matches closely with that of MgB2. Thermodynamic calculations indicate that SiC is chemically stable under the in situ deposition conditions for MgB2 using HPCVD. The MgB2 films on both polytypes show high-quality epitaxy with a Rutherford backscattering channeling yield of 12%. They have Tc above 40 K, low resistivities, high residual resistivity ratios, and high critical current densities. The results demonstrate that SiC is an ideal substrate for MgB2 thin films.