Improved characteristics of (112‾2) Al0.62Ga0.38N film grown with pulsed flow growth technique

• Published in: Materials science in semiconductor processing 2024-10, Vol.181, p.108589, Article 108589
• Main Authors: Dai, Qian, Zhang, Xiong, Fang, Ruiting, Zhang, Lingling, Qi, Zhengqing, Chen, Peng, Chen, Lin, Wang, Shuchang
• Format: Article
• Language: English
• Subjects: (11 [formula omitted] 2) Al0.62Ga0.38N film; Crystal quality; Photoluminescence; Separate NH3 supply; Surface morphology
• ISSN: 1369-8001; 1873-4081
• DOI: 10.1016/j.mssp.2024.108589

Pulsed flow growth (PFG) technique is a simple and effective method to improve the quality of aluminum gallium nitride (AlGaN) alloys. In this work, a reformed three-way PFG was applied to deposit (11 2‾2) plane Al0.62Ga0.38N film, and the separate ammonia (NH3) supply time in a PFG cycle was modulated carefully. It was revealed that the full width at half maximum (FWHM) values of on-axis X-ray rocking curves (XRCs) along [11 2‾3‾]- and [1 1‾00]-direction decreased conspicuously from 0.496 ° to 0.28 ° and from 0.674 ° to 0.451 ° by modifying the separate NH3 supply time to 3 s. Meanwhile, the FWHM values of basal stacking faults (BSFs)-related and prismatic stacking faults (PSFs)-related off-axis XRCs exhibited a reduction of 21.2 % and 17.2 %, respectively. Besides, the ratio of the intensity of BSF-related emission to that of near band emission (NBE) could be suppressed from 0.45 to 0.17. In other words, the crystal quality of (11 2‾2) AlGaN could be ameliorated significantly by optimizing separate NH3 supply time. Furthermore, the root mean square value was also reduced to 0.78 nm. These improvements could be interpreted as the reduced parasitic reaction between TMA and NH3 as well as the boosted migration of Al adatoms.