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The optimal threading dislocation density of AlN template for micrometer-thick Al0.63Ga0.37N heteroepitaxy

C.-Y. Huanga, S. Hagedornb, S. Waldeb, C.-L. Tsaic, Y.-K. Fuc, M. Weyersb

Published in:

J. Cryst. Growth, vol. 600, art. 126910 (2022).


Growth of Si-doped AlN and of Al0.63Ga0.37N on high quality AlN templates grown by HVPE has been investigated. The strain state of Si-doped AlN is thickness-dependent due to the surface-mediated dislocation tilt which induces a tensile strain component. At very low dislocation density in the AlN buffer strain relaxation in micrometer-thick Al0.63Ga0.37N layers is dominated by generation of additional dislocations. As a result, the final threading dislocation density and the surface roughness increase significantly. For a 1.6 µm Al0.63Ga0.37N on 3.4 µm Si-doped AlN bi-layer structure, the optimal threading dislocation density (TDD) of the AlN:Si buffer is estimated to be 7 × 108 cm-2, where the low TDD can be still transferred from the buffer to the thick AlGaN heterostructure without generation of many new dislocations.

a Department of Photonics, College of Electrical and Computer Engineering, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan
b Ferdinand-Braun-Institut (FBH), Gustav-Kirchhoff-Strasse 4, 12489 Berlin, Germany
c Electronic and Optoelectronic System Research Laboratories, Industrial Technology Research Institute, 195, Sec.4, Chung Hsing Rd., Hsinchu, Taiwan


A1. Line defects; A1. Stresses; A3. Metalorganic vapor phase epitaxy; B1. Nitrides; B2. Semiconducting ternary compounds; B3. Light emitting diodes

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