Effects of growth temperature for in-situ deposited SiNx interlayer on structural and optical properties of semipolar (112¯2) AlGaN films

• Published in: Applied surface science 2023-01, Vol.608, p.155262, Article 155262
• Main Authors: Luo, Xuguang, Zhang, Xiong, Qian, Yingda, Fang, Ruiting, Chen, Bin, Shen, Yang, Xu, Shenyu, Lyu, Jiadong, Lai, Mu-Jen, Hu, Guohua, Cui, Yiping
• Format: Article
• Language: English
• Subjects: Basal-plane stacking faults; Crystalline quality; In-situ deposited SiNx interlayers; Photoluminescence; semipolar AlGaN film; Surface morphology
• ISSN: 0169-4332
• DOI: 10.1016/j.apsusc.2022.155262

[Display omitted] •High-quality semipolar (112¯2) AlGaN films were grown with an in-situ SiNx interlayer deposited from 700 to 1100 °C.•Significant improvements in surface morphology, crystalline quality, and optical properties.•The most effective improvement was obtained by the optimized SiNx interlayer deposited at 800 °C.•The degradation in surface morphology and crystalline quality when the SiNx interlayer deposited from 800 to 1100 °C.•A remarkable deterioration in crystalline quality and abrupt increase in the impurity-related yellow band emission at 700 °C or 1100 °C. The dependence of surface morphology, crystalline quality, and optical properties on the growth temperature of in-situ deposited SiNx interlayers in the semipolar (112¯2) AlGaN film was investigated intensively. The in-situ SiNx deposited interlayer was consisted of irregular ultra-thin SiNx nano-scale island-like structures as verified by using scanning electron microscope and energy dispersive spectroscopy. As the growth temperature of the in-situ deposited SiNx interlayer was increased from 700 to 1100 °C, the root mean square roughness of the semipolar (112¯2) AlGaN film increased from 0.72 to 0.87 nm. It was revealed that significant improvements in surface morphology, crystalline quality, and optical properties of the semipolar (112¯2) AlGaN films could be achieved with the insertion of an in-situ deposited SiNx interlayer grown at a temperature between 800 and 1000 °C. These achievements are owing to the formation of the SiNx nano-scale island-like structures that like the well-known patterned sapphire substrate played a crucial role in the reduction of the basal-plane stacking faults (BSFs) and the suppression of the BSFs- and other defects-related emissions in the semipolar (112¯2) AlGaN films.