Characteristics of single-crystal AlN films grown on ferromagnetic metal substrates

We have demonstrated the first single-crystal growth of AIN films on Fe substrates using pulsed laser deposition and investigated their structural properties. Stepped and terraced surfaces of the Fe(110) substrates have been achieved by UHV annealing. Although a low quality AIN film, with randomly oriented polycrystalline grains, grows at a substrate temperature of 510 degrees C, a single-crystal AIN film is achieved by lowering the growth temperature down to 430 degrees C. The distributions of crystal orientations in the tilt and the twist directions for a AIN film measured by electron backscattered diffraction (EBSD) are 0.26 degrees and 0.58 degrees, respectively. Neither 30 degrees rotational domains nor cubic phase domains exist in the AIN films. We have also found that the intermixing reactions between AIN and the Fe substrates are fully suppressed and the heterointerface is atomically abrupt. These results indicate that low temperature PLD growth technique allows us to grow single-crystal AIN on ferromagnetic substrates with an atomically abrupt interface.