Evolution of structural and morphological properties in GaN films on Si and glass substrates

Abstract

© 2025 Elsevier LtdThis study investigates the influence of thickness on the structure and morphology of sputtered wurtzite GaN thin films and evaluates their potential as piezoelectric materials for surface acoustic wave (SAW) devices. High-quality GaN films were deposited on Si(100) and glass substrates via reactive magnetron sputtering under optimized conditions. X-ray diffractometry (XRD), Raman spectroscopy, and transmission electron microscopy (TEM) analysis confirmed a preferential c-axis orientation. A detailed assessment of the crystalline quality and structural properties revealed that films grown for 6 h on Si substrates exhibited superior crystallinity and lower defect density. However, increasing film thickness led to higher surface roughness, which may impact SAW device performance. These findings highlight the viability of sputtered GaN films for SAW applications, provided that deposition parameters are carefully controlled to balance crystallinity and surface roughness. This work demonstrates the potential of cost-effective sputtering technique for producing GaN films suitable for high-frequency SAW devices.

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