Investigation of AlN buffer layers on 6H-SiC for AlInN HEMTs grown by MOVPE

✍ Scribed by H. Behmenburg; C. Giesen; R. Srnanek; J. Kovac; H. Kalisch; M. Heuken; R.H. Jansen

• Publisher: Elsevier Science
• Year: 2011
• Tongue: English
• Weight: 839 KB
• Volume: 316
• Category: Article
• ISSN: 0022-0248
• DOI: 10.1016/j.jcrysgro.2010.12.058

✦ Synopsis

In this paper, the influence of V/III molar flow ratio during AlN growth on SiC on growth mode and in-plane strain is investigated. AlN layers of $ 300 nm thickness were grown by metal-organic vapor phase epitaxy (MOVPE) on semi-insulating 6H-SiC and the V/III ratio was changed from 240 to 8200 on four samples by varying the ammonia flux only. The surface morphology was investigated by atomic force microscopy and a growth mode change from two-dimensional to three-dimensional with increasing V/III ratio was observed. Investigation by X-ray diffraction (XRD) reciprocal space mapping (RSM) shows a strong dependence of the AlN peak position on the V/III ratio indicating a significant change in the lattice constants. Results from micro-Raman spectroscopy measurements verify that the AlN in-plane strain can be converted from tensile to compressive when high V/III ratios are applied. Further, an impact of the AlN properties on coalescence time for subsequently grown GaN was found.