Berlin 2015 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
HL: Fachverband Halbleiterphysik
HL 98: Nitrides: Bulk material, films, surfaces and quantum wells
HL 98.4: Vortrag
Freitag, 20. März 2015, 10:15–10:30, EW 201
Aberration-corrected-STEM investigation of epitaxial GaN thin films formed by ion-beam based post-nitridation of Ga droplets — •David Poppitz, Andriy Lotnyk, Jürgen W. Gerlach, and Bernd Rauschenbach — Leibniz-Institut für Oberflächenmodifizierung e. V., Permoserstr. 15, D-04318 Leipzig
GaN is a widely used semiconductor material in optoelectronics applications due to its optical properties. By increasing the crystalline quality, the emission efficiency for light emitting devices can be improved. Here, GaN thin films were produced in a system usually used for ion-beam assisted molecular-beam epitaxy (IBA-MBE) on 6H-SiC-, Al2O3- and γ-LiAlO2-substrates. In the first step of the deposition process, Ga-droplets were deposited on the substrates. In the second step, a post-nitridation process of Ga droplets by a hyperthermal nitrogen ion beam with ion energies less than 25 eV was used to form the GaN thin films.
The thin films characterization was done by using a state of the art FEI Titan3 G2 60-300kV probe aberration-corrected scanning transmission electron microscope (STEM). It was found that coalesced GaN thin films with film thicknesses less than 30 nm can be achieved by this preparation method. The detailed investigation shows different types of defects such as grain boundaries and stacking faults in the epitaxial, differently oriented films. However, the crystalline quality of GaN thin films was dependent on the substrate material.