Direct growth of single-domain epitaxial AlN films on Si(111) by RF/DC magnetron sputtering

• DOI: 10.35848/1347-4065/adc21c
• Publication Date: 2025-03-18T22:55:52Z
• Authors: Fong-Zhi Chen; Wei-Chun Chen; Itagaki Katsunori; Tung-Yuan Yu; Wei-Lin Wang; Yu-Wei Lin; Chao-Te Lee; Kodama Akira; Jin-Yu Shih; Stanley Chen

Abstract In this study, epitaxial aluminum nitride (AlN) films were deposited on 6′ p-type Si(111) substrate through RF/DC magnetron sputtering with an RF bias and two N2/Ar flow rates. We discussed the effects of nitrogen flow rate on the microstructure and crystal domains of AlN/Si(111) at 800 °C. The in-plane X-ray diffraction (In-plane XRD) pattern revealed that AlN/Si(111) with a N2/Ar flow ratio of 0.63 exhibited two domains. As the N2 flow rate decreased, the AlN film showed improved crystalline quality. Furthermore, the in-plane XRD and transmission electron microscopy results showed that single-domain AlN was epitaxially grown on Si(111) in a N2/Ar flow ratio of 0.43. Also, in-plane epitaxial relationships between the AlN film and Si(111) substrate were determined to be AlN(0002)//Si(111) and AlN[

11

2

̅

0

]//Si[220]. The results leverage optimized process parameters to achieve single-domain epitaxy, confirmed by the in-plane epitaxial alignment of AlN on Si(111), which reduces lattice mismatch. These findings highlight the potential of high-quality sputtered AlN films and their evolving applications in high-power III-nitride heteroepitaxy.