High quality epitaxial piezoelectric and ferroelectric wurtzite Al_1-xSc_xN thin films

2024/08/21 by Yang Zeng, Zeng, Yang, Yihan Lei +23
Engineering · Materials Science · #Acoustic Wave Resonator Technologies #Ferroelectric and Piezoelectric Materials #Advanced MEMS and NEMS Technologies

paper · pdf · doi:10.48550/arxiv.2408.11379

Abstract

Piezoelectric and ferroelectric wurtzite are promising to reshape modern microelectronics because they can be easily integrated with mainstream semiconductor technology. Sc doped AlN (Al_1-xSc_xN) has attracted much attention for its enhanced piezoelectric and emerging ferroelectric properties, yet the commonly used sputtering results in polycrystalline Al_1-xSc_xN films with high leakage current. Here we report the pulsed laser deposition of single crystalline epitaxial Al_1-xSc_xN thin films on sapphire and 4H-SiC substrates. Pure wurtzite phase is maintained up to x = 0.3 with minimal oxygen contamination. Polarization is estimated to be 140 μC/cm² via atomic scale microscopy imaging and found to be switchable via a scanning probe. The piezoelectric coefficient is found to be 5 times of undoped one when x = 0.3, making it desirable for high frequency radiofrequency (RF) filters and three-dimensional nonvolatile memories.

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