Realization of Highly c-Axis-Oriented AlN Textured Films on Wafer-Level Polycrystalline Mo Substrate via Magnetron Sputtering
Journal article, 2026
In the field of semiconductor display technology, GaN epitaxial growth has long been constrained by the performance bottlenecks of substrates and buffer layers. Current homogeneous substrates are costly and size-constrained, while heterogeneous substrates, such as sapphire and SiC, suffer from significant lattice mismatch with GaN, limiting large-area device fabrication. This study used a wafer-level polycrystalline Mo substrate, attributed to its excellent electrical conductivity, thermal conductivity, high melting point, chemical stability, and moderate thermal expansion coefficient-properties that render it a favorable substrate for growing high-quality GaN functional layers. Additionally, incorporating an AlN buffer layer between Mo and GaN further alleviated the lattice mismatch. Notably, highly c-axis-oriented AlN thin films are a prerequisite for fabricating high-quality and uniform GaN layers. Through precise control of magnetron sputtering parameters, the highly c-axis-oriented AlN textured thin films were successfully achieved on polycrystalline Mo substrates, achieving epitaxial growth with exclusive (002) plane orientation. This effectively alleviates lattice mismatch and stress between the substrate and GaN functional layer, thereby enhancing the crystalline quality. Further studies revealed that the chamber environment postglow discharge exerts a critical impact on the orientation and crystalline quality of AlN films. By precisely optimizing the process, the intensity of the AlN (002) diffraction peak was enhanced by 108% and surface roughness was reduced by 75%. The study demonstrates high uniformity on 4 in. Mo substrates, which was a key technology for low-cost, large-area Micro-LED epitaxy growth, and provides a new path for the industrialization of GaN-based devices.
Author
Shuaishuai Wang
Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China
Fuzhou University
Jia Chen
Fujian Acetron New Materials Co. Ltd
Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China
Yang Li
Xiamen Changelight
Yijian Zhou
Fuzhou University
Caihong Yan
Fuzhou University
Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China
Taifu Lang
Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China
Fuzhou University
Xin Lin
Fuzhou University
Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China
Kaixin Zhang
Fujian Agriculture and Forestry University (FAFU)
Zhihe Lin
Fujian Acetron New Materials Co. Ltd
Tailiang Guo
Fuzhou University
Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China
Qun Yan
Fuzhou University
Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China
Jie Sun
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics
Crystal Growth & Design
1528-7483 (ISSN) 1528-7505 (eISSN)
Vol. 26 2 874-885Subject Categories (SSIF 2025)
Condensed Matter Physics
DOI
10.1021/acs.cgd.5c01436