Dresden 2009 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 9: Poster 1
HL 9.23: Poster
Montag, 23. März 2009, 14:30–17:00, P2
MOVPE growth of AlGaN films — •Ö. Savaş1, J. Stellmach1, C. Meissner1,2, M. Pristovsek1, and M. Kneissl1 — 1TU Berlin, Institut für Festkörperphysik EW6-1, Hardenbergstr. 36, 10623 Berlin, Germany — 2ISAS Berlin, Albert-Einstein-Str. 9, 12489 Berlin, Germany
For UV light emitting diodes (LEDs) the growth of AlGaN with high Al-content is essential. By varying the Al-content in AlxGax−1N emission energies between 3.4 and 6.2 eV can be achieved.
We have investigated the growth of AlGaN on GaN/sapphire templates by metal-organic vapour phase epitaxy (MOVPE) in a Thomas Swan vertical close coupled showerhead reactor. The influence and understanding of the strong gas phase prereactions between trimethylaluminium (TMAl) and ammonia (NH3) are important for high quality AlGaN growth. To study these critical prereactions these effects of growth parameters like NH3 and TMAl partial pressures, total reactor pressure and growth temperature on the Al-incorporation has been investigated. We found that the growth rate decreased with increasing temperature and the Al-content increased proportional to the square root of the TMAl partial pressure. Further investigation, in particular the effects of the gap between the showerhead (inlet for the vapours) and the substrate on the prereaction are under way.