Formation of self-organized nanodots on GaN surface by Ar-ion implantation
poster presentation: Monday 2010-08-23 05:00 PM - 07:00 PM in section Ion-driven self-organization, nanopatterning
Last modified: 2010-06-02
Abstract
The most recent development in the area of ion beam processing of materials is ion induced synthesis of self-organized nanostructures at the surfaces of semiconductors. Group-III semiconductors have attracted a great deal of interest due to their wide applications in optoelectronics. In particular, GaN nanodots are considered to be more useful because they are known to be efficient light emitters even when grown on a defective material thanks to their carrier confinement properties.
In this work, we have used 0.5 µm thick GaN films grown on Si(111). Prior to the growth of the GaN films, a buffer layer of AlGaN (1 µm thick) was grown on Si(111) substrate. The films were well characterized by Rutherford backscattering spectrometry (RBS-C) and x-ray diffraction (XRD) techniques. Subsequently, GaN samples were implanted with normally incident 60 keV Ar-ions to fluences in the range of 1×1016 to 1×1017 ions cm-2. Room temperature implantations were carried out at a uniform target current of 5 µA cm-2. The evolution of morphology on GaN surfaces was investigated by atomic force microscopy (AFM). The results show that dot formation starts at the lowest fluence itself and the dot size increases with increasing ion fluence. We employed high-resolution Auger electron spectroscopy (AES) for analyzing the chemical composition of these samples. AES analysis of the ion sputtered surface clearly shows Ga enrichment of the sputtered GaN surface. RBS-C results show a systematic reduction in the GaN film thickness. The results are interpreted in the light of sputter erosion by energetic ions.
Author(s) affiliation:
L. M. C. Pereira, 1 Instituut voor Kern- en Stralingsfysica and INPAC, K.U. Leuven, Celestijnenlaan 200D, B-3001 Leuven, Belgium, Belgium
T. Skeren, 1 Instituut voor Kern- en Stralingsfysica and INPAC, K.U. Leuven, Celestijnenlaan 200D, B-3001 Leuven, Belgium, Belgium
J. Demeulemeester, 1Instituut voor Kern- en Stralingsfysica and INPAC, K.U. Leuven, Celestijnenlaan 200D, B-3001 Leuven, Belgium, Belgium
A. Franquet, 3 Process Technology Division, IMEC, 75 Kapeldreef, B-3001 Leuven, Belgium, Belgium
K. Temst, 1 Instituut voor Kern- en Stralingsfysica and INPAC, K.U. Leuven, Celestijnenlaan 200D, B-3001 Leuven, Belgium, Belgium
A. Vantomme, 1 Instituut voor Kern- en Stralingsfysica and INPAC, K.U. Leuven, Celestijnenlaan 200D, B-3001 Leuven, Belgium, Belgium
*presenting author