Investigating Crystallography and Thickness Distribution of Aluminium Nitride Thin Films Prepared by Magnetron Sputtering on Silicon Wafer

This study utilized radio frequency magnetron sputtering to deposit aluminum nitride (AlN) thin film onto a silicon wafer at room temperature. The investigation focused on characterizing the thin film's crystal structure and thickness distribution across different positions within a 4-inch wafer area, utilizing both static and rotated substrate holders. Generally, the X-ray diffraction (XRD) spectrum shows three main crystal planes of (100), (002), and (101) that belong to AlN. Static holder conditions exhibited significant variations among crystal planes, indicating non-homogeneous deposition. Particularly, a strong (002) peak was determined near the target source, as expected due to the plasma concentration and higher energy of sputtering particles directed toward the substrate at that specific position. On the other hand, rotated holders produced nearly identical spectra but with weaker peaks due to shadowing and stagnation effects. Deposition angle and particle energy impacted crystal orientation and XRD peak intensities. The standard deviation for thickness was 43.22 nm with static holders, reduced to 19.45 nm with rotated holders, showing uniform thickness distribution with minimal variation across different positions. This research aids in understanding large-area thin film deposition, particularly for AlN templates in microelectromechanical systems (MEMS) applications and as buffer layers for gallium nitride (GaN) devices.