Münster 1999 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 30: Epitaxie

HL 30.2: Vortrag

Donnerstag, 25. März 1999, 10:45–11:00, H3

The polarity of AlN films on Si substrates grown by plasma-assisted molecular beam epitaxy — •Wo. Richter1, V. Lebedev1,2, B. Schröter1, G. Kipshidze2, and U. Kaiser11Institut für Festkörperphysik, FSU Jena, Max-Wien-Platz 1, 07743 Jena — 2Ioffe Institut, St. Petersburg, Rußland

The AlN/Si-heterosystem shows very promising results as a basis for surface acoustic wave applications and as a template for III-nitride-based electronics and GaN-based optoelectronic devices. The molecular beam epitaxy of high quality, atomically flat AlN films of both polarities on Si(111) substrates was investigated as a function of growth and nucleation parameters. The nucleation conditions of epitaxial AlN on chemically clean, atomically flat Si surface were found to be critical to form the AlN films either with Al- or N-face. The existance of an initial, 7x7 reconstructed Si(111) surface is found to be important to provide proper initial island formation and subsequent two-dimensional growth of AlN (0001) or (0001) epitaxial films, despite the 23.4% misfit in the AlN/Si system. Possible influence of an initial III-V ratio on the polarity of the nucleating epitaxial layer as well as polarity-dependent (3x3), (3x6), (6x6) and (2x6) AlN-surface reconstructions observed by RHEED are discussed. AlN film polarity determination has been performed by XPD and by observation of well-known polarity-dependent GaN-surface reconstructions [1] during subsequent GaN growth on the AlN/Si(111) template. Finally, the AlN layers were characterized by AFM, XRD, TEM and AES measurements.

[1] Smith A.R. et. al. J.Appl.Phys. 72, 2114 (1998)

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