Fabrication and Properties of AlN Film on GaN Substrate by Using Remote Plasma Atomic Layer Deposition Method

AlN films on n-type GaN (0001) were prepared using a remote-plasma atomic-layer-deposition (RPALD) technique with a trimethylaluminum(TMA) precursor and nitrogen/hydrogen, argon/hydrogen radicals ranging in temperature from room temperature (RT) to 500 degrees C. The growth rate per cycle was varied with the substrate temperature from 2.3 angstrom/cycle at R. T. to 0.9 angstrom/cycle at 500 degrees C. X-ray diffraction results showed that the as-grown AlN films on GaN substrates had amorphous phase structures. The estimated interface trap density measured was about 2.4 x 10(11)/cm(2) eV at 1.08 eV below the conduction band edge. The leakage current densities measured at room temperature was about 5 x 10(-10) A/cm(2) under a field of 1 MV/cm.