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HL: Halbleiterphysik

HL 13: III-V Halbleiter II

HL 13.5: Talk

Friday, March 4, 2005, 16:00–16:15, TU P-N202

Influence of sapphire nitridation of MOVPE growth of InN — •C. Werner, M. Drago, M. Pristovsek, and W. Richter — TU-Berlin, Institut für Festkörperphysik, Hardenbergstr. 36, 10623 Berlin

The growth of InN in MOVPE is a challenging issue. Subsequently, the quality of the available InN layers is poor and fundamental properties of this material (i.e. the value of the bandgap energy) are still under discussion. Therefore, there is a strong demand to improve the InN. Usually our InN epitaxy is a three step process, consisting of nitridation, nucleation layer (commonly low-temperature and defective) and thick InN layer growth. In this work we study the effects of different nitridation procedures on the quality of InN layers. With in-situ spectroscopic ellipsometry (SE) we are able to see the progress of nitridation and get an insight into the nitridation process. We expose sapphire to ammonia in either nitrogen or hydrogen carrier gas. Both, the resulting nitrided substrate and the InN layer grown on top are characterised ex-situ with atomic force microscopy and X-ray diffraction. We found that hydrogen as carrier gas during nitridation has a negative effect on the crystal quality.