High-Temperature Annealing Induced He Bubble Evolution in Low Energy He Ion Implanted 6H-SiC

• Published in: Chinese physics letters Vol. 34; no. 5; pp. 40 - 43
• Main Author: 刘玉柱 李炳生 张莉
• Format: Journal Article
• Language: English
• Published: 01.05.2017
• Subjects: Ostwald熟化; 低温退火; 低能量; 氦离子注入; 演化规律; 碳化硅; 纳米气泡; 诱导
• ISSN: 0256-307X; 1741-3540
• DOI: 10.1088/0256-307X/34/5/052801

Bubble evolution in low energy and high dose He-implanted 6H-SiC upon thermal annealing is studied. The （0001）-oriented 6H-SiC wafers are implanted with 15keV helium ions at a dose of 1×10^17 cm^-2 at room temperature. The samples with post-implantation are annealed at temperatures of 1073, 1173, 1273, and 1473K for 30rain. He bubbles in the wafers are examined via cross-sectional transmission electron microscopy （XTEM） analysis. The results present that nanoscale bubbles are almost homogeneously distributed in the damaged layer of the as-implanted sample, and no significant change is observed in the He-implanted sample after 1073 K annealing. Upon 1193 K annealing, almost full recrystallization of He-implantation-induced amorphization in 6H-SiC is observed. In addition, the diameters of He bubbles increase obviously. With continually increasing temperatures to 1273K and 1473 K, the diameters of He bubbles increase and the number density of lattice defects decreases. The growth of He bubbles after high temperature annealingabides by the Ostwald ripening mechanism. The mean diameter of He bubbles located at depths of 120-135 nm as a function of annealing temperature is fitted in terms of a thermal activated process which yields an activation energy of 1.914＋0.236eV.