Fabrication of particle free epitaxal AlN thin films by reactive PLD combined with an electron beam and a rotating crucible

An AlN epitaxial film without projections or spiral growth features was successfully fabricated on a (0 0 0 1) sapphire substrate by reactive laser ablation of a liquid Al target in NH3 using a 248 nm laser. The liquid Al target was prepared with an electron beam in a rotating crucible. The surface of the rotating liquid Al target was always smooth. Spiral growth features were greatly suppressed. AlN films have a surface roughness less than 0.3 nm. The X-ray rocking curve's narrowest FWHM was 180 arcsec, which is nearly identical to that recently reported in films grown by MOCVD or reactive MBE.