Parasitic AlxOyNz surface defects on high-temperature annealed AlN and their role in hillock formation
2023 | journal article. A publication with affiliation to the University of Göttingen.
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Parasitic AlxOyNz surface defects on high-temperature annealed AlN and their role in hillock formation
Peters, L.; Meyer, T.; Margenfeld, C.; Spende, H. & Waag, A. (2023)
Applied Physics Letters, 123(11) art. 112104. DOI: https://doi.org/10.1063/5.0170006
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Details
- Authors
- Peters, Lukas; Meyer, Tobias; Margenfeld, Christoph; Spende, Hendrik; Waag, Andreas
- Abstract
- High quality AlN buffer layers on sapphire wafers are a prerequisite for further improving UV LEDs. In addition, AlN templates with low screw-dislocation density might be interesting for future power electronic devices. High-temperature annealing (HTA) has proven to be a viable route to improve the crystallinity of sputtered or thin metalorganic vapor-phase epitaxy (MOVPE) AlN layers. In this work, the influence of two different pretreatment conditions prior to the MOVPE regrowth on HTA AlN templates was analyzed. AFM studies found a hillock density of roughly 106 cm−2 in regrown AlN, whereby such hillocks could no longer be observed after introducing harsher bake conditions. The origin of the observed hillock defects was clarified by using different TEM-related measurement techniques. Based on the TEM and AFM findings, a double-spiral enhanced growth mode that emits concentric surface steps on top of γ-AlON islands is suggested as a underlying mechanism for hillock formation.
- Issue Date
- 2023
- Journal
- Applied Physics Letters
- ISSN
- 0003-6951
- eISSN
- 1077-3118
- Language
- English
- Sponsor
- Deutsche Forschungsgemeinschaft 10.13039/501100001659