In this work, systematic investigations were conducted to explore the effects and mechanisms of sputtering conditions on the structure and piezoelectric properties of aluminum nitride (AlN) films. Specifically, the contribution of a high-temperature-grown AlN seed layer to the performance of piezoelectric AlN films with molybdenum (Mo) electrodes was demonstrated. Compared with the unseeded AlN/Mo structure, the seeded system exhibited superior crystallization quality, reduced internal stress, and well-maintained surface morphology. Piezoresponse force microscopy measurements revealed a significant enhancement in the piezoelectric coefficient (d33) from 0.7 to 6.2 pm/V after incorporating the AlN seed layer. These results indicate that the high-temperature-grown AlN seed layer simultaneously improves both the structural integrity and piezoelectric performance of AlN films on Mo electrodes, providing a novel strategy for the development of high-performance AlN-based microelectromechanical system devices.
Yin et al. (2026) studied this question.