Effect of nitrogen pressure on the properties of AlN films grown on nitrided Al(1 1 1) substrates by pulsed laser deposition

• High-quality AlN films have been epitaxially grown on nitrided Al(1 1 1) substrates.
• Effect of nitrogen pressure on the properties of AlN film has been studied in detail.
• Abrupt AlN/Al achieved in this work is of great importance.

AlN films have been epitaxially grown on nitrided Al(1 1 1) substrates with various nitrogen pressures by pulsed laser deposition with an in-plane alignment of AlN[11–20]//Al[1–10]. The effect of nitrogen pressure on the surface morphologies and structural properties of AlN films is studied in detail. It reveals that AlN films grown at appropriate pressure exhibit very flat and smooth surface with a surface root-mean-square roughness of 1.1 nm, and abrupt interface; while AlN films grown at other pressures show poorer properties. This work presents an optimized growth conditions for the growth of high-quality AlN films for the application of film bulk acoustic wave resonators and surface acoustic wave devices that ask for the flat surface and abrupt interface.