Synthesis of high-quality A1N films on (La,Sr) (Al,Ta)O_3 substrates by pulsed laser deposition

摘要

High-quality A1N films have been grown on (La_(0.3),Sr_(0.7)) (Al_(0.65),Ta_(0.35))O_3(LSAT) substrates by pulsed laser deposition (PLD) with an in-plane alignment of AlN[11-20]//LSAT[1-10]. The as-grown ～300-nm-thick AlN films grown at 450 ℃ exhibit very smooth surface with a root-mean-square roughness of 1.8 nm. There is no interfacial layer existing between AlN and LSAT, indicating the sharp and abrupt interfaces. Furthermore, as the increase in growth temperature, the surface morphologies, crystalline qualities, interfacial properties of as-grown AlN increase initially and then deteriorate gradually. This work of achieving high-quality AlN films by PLD is of paramount importance in the application of acoustic filters that require abrupt interfaces and flat surfaces.