Preparation of epitaxial AlN films by electron cyclotron resonance plasma‐assisted chemical vapor deposition on Ir‐ and Pt‐coated sapphire substrates

AlN epitaxial films have been fabricated on Ir‐ and Pt‐coated α‐Al2O3 substrates via electron cyclotron resonance plasma‐assisted chemical vapor deposition (ECRPACVD) using an AlBr3‐N2‐H2‐Ar gas system at substrate temperatures ranging from 500 to 700 °C. The epitaxial relationships between AlN films and substrates were determined by x‐ray diffraction, x‐ray pole figure, and reflection high‐energy electron diffraction. The results are useful in practical applications, such as AlN/metal/α‐Al2O3 structure in surface acoustic wave (SAW) devices.