Annihilation and Regeneration of Defects in (11(2)over-bar2) Semipolar AlN via High-Temperature Annealing and MOVPE Regrowth
Annihilation and Regeneration of Defects in (11(2)over-bar2) Semipolar AlN via High-Temperature Annealing and MOVPE Regrowth
复制标题
通过高温退火和 MOVPE 再生长消除和再生 (112Ì2) 半极性 AlN 中的缺陷
DOI：
10.1021/acs.cgd.1c00086
复制
发表时间：
2021-04-19
影响因子：
3.8
通讯作者：
Ye, Jichun
中科院分区：
文献类型：
--
作者：
Chen, Li;Lin, Wei;Ye, Jichun
Semipolar III-nitrides have attracted great attention due to their weak polarization field for optoelectronic devices. High-quality AlN is a perfect template in the epitaxial growth of AlGaN-based ultraviolet optical devices. In this work, (11 (2) over bar2) semipolar AlN was grown on m-plane sapphire by the hierarchical growth mode. A high density of extended defects due to the lattice mismatch and anisotropic growth rate is identified in the as-grown AlN thin film. The influence of thermal annealing and AlN regrowth on the evolution of stacking faults and dislocations in AlN was thoroughly investigated by high-resolution transmission electron microscopy. Extending defects turned into partial dislocations after high-temperature treatment, by which the stacking faults were buried inside the AlN template, incapable of propagating into the AlN regrowth layer. As a result, the AlN regrowth layer exhibits superior crystalline quality. However, compressive strain is found after high-temperature annealing (HTA), which introduces new defects in the AlN regrowth layer. Strain management is demonstrated to be crucial for the quality control of the AlN layer. Overall, high-temperature annealing and regrowth processes proved to be stable and repeatable techniques in the realization of high-efficiency semipolar UV semiconductor devices.
