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HL: Fachverband Halbleiterphysik

HL 56: Non- and Semi-polar Group-III-Nitrides

HL 56.7: Vortrag

Donnerstag, 25. März 2010, 15:30–15:45, H15

Plasma supported cleaning of galliumnitride (1120) surfaces — •Hendrik Geffers, Christian Schulz, Jan Ingo Flege, Thomas Schmidt, and Jens Falta — Institute of Solid State Physics, University of Bremen, 28359 Bremen, Germany

In this work we investigated the cleaning of non-polar galliumnitride (1120) surfaces of metal organic chemical vapor phase epitaxy (MOVPE) grown samples by thermal annealing and sequential nitrogen plasma treatment. The chemical composition of the surface was analysed by x-ray photoelectron spectroscopy (XPS) before the treatment and after every cleaning step. The morphology and structure of the sample’s surface was observed by scanning tunneling microscopy (STM) and low energy electron diffraction (LEED).

The XPS data of the untreated samples show large carbon and oxygen contaminations. The STM images exhibit a high roughness which is also reflected in the LEED patterns by a high background and diffuse diffraction spots. Most of the carbon contamination was found to be removed after the thermal annealing, while the amount of oxygen contamination could significantly be lowered with the plasma treatment. The STM images show a smoother surface after the cleaning process, this is also reflected in the LEED patterns by sharper diffraction spots and a lower background.