Dresden 2014 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 17: Ion and Electron Beam Induced Processes

DS 17.2: Vortrag

Dienstag, 1. April 2014, 14:15–14:30, CHE 91

Gallium Nitride Films by Ion-Beam Assisted MBE - Effects of Long-Term Ion Irradiation — •Annemarie Finzel, Jürgen Gerlach, Frank Frost, Jan Lorbeer, and Bernd Rauschenbach — Leibniz-Institut für Oberflächenmodifizierung e.V. (IOM Leipzig), Permoserstraße 15, D-04318 Leipzig, Germany

One technique to grow GaN thin films of high quality and purity is ion-beam assisted molecular-beam epitaxy (IBA-MBE). Ga is evaporated in an effusion cell and adsorbs at the heated substrate (superpolished 6H-SiC(0001) at 700 ^∘C ) surface, while it is bombarded by hyperthermal N ions ( E_kin ≤ 25 eV) generated by a hollow-anode plasma source. The aim of the present study is to examine whether a long-term irradiation with hyperthermal N ions has an effect on an already deposited GaN film. For this purpose, heated ( 700 ^∘C , 600 ^∘C ) and non-heated (RT) GaN films were irradiated up to 6 h with N ions. To test that there is no thermal GaN decomposition one film was heated for several hours at the typical deposition temperature ( 700 ^∘C ) without ion irradiation. The investigations using RHEED, UHV-STM and AFM have shown that a long (2 h) irradiation with hyperthermal N ions after the film deposition has an effect on the surface of the GaN films. The roughness of the irradiated samples was increased and a large amount of holes and canyons was formed which could be due to sputtering or due to a rearrangement of atoms at the GaN film surface. It could be proven that a long heating of the GaN film at 700 ^∘C and a long irradiation at RT has no visible influence on the surface structure and topography. The effects of the ion irradiation will be discussed.