Step-flow growth of Al droplet free AlN epilayers grown by plasma assisted molecular beam epitaxy. (8th September 2022)

• Record Type: Journal Article
• Authors: Shao, Pengfei; Li, Siqi; Li, Zhenhua; Zhou, Hui; Zhang, Dongqi; Tao, Tao; Yan, Yu; Xie, Zili; Wang, Ke; Chen, Dunjun; Liu, Bin; Zheng, Youdou; Zhang, Rong; Lin, Tsungtse; Wang, Li; Hirayama, Hideki
• Is Part Of: Journal of physics. Volume 55:Number 36(2022)
• Publication Date: 2022-09-08
• Subjects: AlN -- Al modulation epitaxy -- Al droplet free -- step flow; Physics -- Periodicals; 530
• DOI: 10.1088/1361-6463/ac79dd
• Languages: English
• ISSNs: 0022-3727

Abstract

Abstract: We have investigated an Al modulation epitaxy (AME) method to obtain step-flow growth of Al droplet free AlN layers by plasma assisted molecular beam epitaxy (MBE). At the usual growth temperature of (Al)GaN/AlN heterostructures, Al atom migration and desorption rate are very low and consequently it is very difficult to avoid the formation of Al droplets on AlN growth front by conventional MBE growth method. By adopting the AME growth method, such a difficulty has been effectively overcome and step flow growth mode of AlN has been clearly observed. By optimizing the AME growth time sequence, namely, AlN growth time and N radical beam treatment time, Al droplet free AlN layers with step flow growth characteristics have been obtained, with atomic flat surfaces and an average atomic step width of ∼118 nm at 970 °C–1000 °C, which is still suitable to grow (Al)GaN/AlN heterostructures by MBE.