Characteristics and polarization-enhanced model of wurtzite aluminum nitride thin films synthesized on Si(100) substrates by pulsed laser deposition

AlN thin films were fabricated on silicon (100) substrates by pulsed laser deposition and their properties are investigated. Our results indicate that the AlN films have a wurtzite crystalline structure with (002) preferential orientation over a large range of temperatures from room temperature to 800 °C. With an increase in substrate temperature, the films undergo a transition from nanocrystalline to large polycrystalline morphology, and at the same time the surface roughness increases due to larger columnar grain size. Electrical measurements show that there is a high dynamic charge density in the AlN films, and a polarization-enhanced mechanism is proposed to interpret the voltage–charge hysteresis loops observed in the samples.