Overcoming the excessive compressive strain in AlGaN epitaxy by introducinghigh Si-doping in AlN templates
Jpn. J. Appl. Phys., vol. 59, no. 7, pp. 070904 (2020).
© 2020 The Japan Society of Applied Physics. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the Japan Society of Applied Physics.
The influence of compressive strain in high-quality AlN templates on the subsequent growth of AlGaN-based device layers was investigated. The AlN templates showed compressive strain of ∼-0.29% and threading dislocation densities (TDDs) below 6.5 × 108cm-2. By introducing high Si-doping in MOVPE-grown AlN, the compressive strain was relaxed while preserving the low TDD. By this method, the low TDD was transferred from the AlN template to the micron-thick n-Al0.63Ga0.37N. A 275 nm LED was demonstrated with a ∼2.5 times power enhancement than the same LED on conventional MOVPE-grown AlN template under low current injection. The maximum external quantum efficiency (EQE) was enhanced from 1.6% to 2.2% with an improved n-AlGaN.
1 Electronic and Optoelectronic System Research Laboratories, Industrial Technology Research Institute, 195, Sec. 4, Chung Hsing Rd., Hsinchu, 31057, Taiwan
2 Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Strasse 4, 12489 Berlin, Germany
3 Graduate Institute of Photonics and Optoelectronics and Department of Electrical Engineering, National Taiwan University, Taipei 10617, Taiwan