Epitaxial growth of high quality AlN films on Si substrates

Quality-enhanced AlN epitaxial films on Si substrates with Al buffer layer have been grown by the combination of molecular beam epitaxy (MBE) and pulsed laser deposition (PLD) technologies. MBE is deployed to grow Al buffer layer at first, and PLD is used to grow AlN epitaxial films on the Al buffer layer. It is found that as the increase in the growth temperature, the property of as-grown ~300 nm-thick AlN epitaxial films is first increased and then decreased, and shows an optimized value at 750 °C. The as-grown ~300 nm-thick AlN epitaxial films grown at 750 °C show full-width at half-maximums of AlN (0002) and AlN () of 0.45° and 0.80°, respectively, a root-mean-square surface roughness of 1.4 nm. This work provides an effective approach for the growth of high-quality AlN epitaxial films on Si substrates for the future application of AlN-based devices.