文摘

In this work, scandium aluminum nitride alloy (ScAlN) thin films were prepared on c-sapphire substrates by DC reactive magnetron sputtering with a scandium aluminum alloy (Sc0.06Al0.94) target. The crystal orientation and surface morphology were detected by XRD and AFM, respectively. The electrical properties were analyzed by a standard ferroelectric test system and piezoelectric response force microscopy. The results show that the sputtering atmosphere, including N2/Ar flow ratio and sputtering pressure, appears to be important to influence the crystal quality and electrical properties of ScAlN films. With the N2/Ar flow ratio increasing from 3.1:7 to 3.6:7, the crystal orientation and surface morphology of ScAlN films firstly improves and then gets worse. Meanwhile, the electrical qualities of the films performs a similar variation. When the sputtering pressure increases from 0.3 to 0.7?Pa, the properties of the films change obviously too, and the best sputtering pressure is determined as 0.5?Pa. Finally, highly c-axis ScAlN films can be obtained with a N2/Ar flow ratio of 3.4:7 and a sputtering pressure of 0.5?Pa, and the FWHM value of the rocking curve, the RMS roughness, the resistivity, the dielectric constant ?r and piezoelectric constant d33 are 2.6°, 2.650?nm, 2.9?×?1012?Ω/cm, 12.2 and 8.1?pC/N, respectively.