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HL: Fachverband Halbleiterphysik

HL 68: Nitrides: Preparation and characterization II

HL 68.7: Vortrag

Donnerstag, 19. März 2020, 16:30–16:45, POT 112

V-groove patterning of 3C-SiC/Si(001) substrates for cubic GaN epitaxy — •Mario Littmann, Dirk Reuter, and Donat J. As — Universität Paderborn, Department Physik, Warburger Straße 100, 33098 Paderborn

Meta-stable cubic GaN (c-GaN) can be grown by molecular beam epitaxy on 3C-SiC/Si(001) substrates. However, the high lattice mismatch results in many crystal defects. A possible solution to reduce the amount of defects is the pre-pattering of the substrate. In previous works, it was reported that it is possible to create defect-free c-GaN inside a V-shaped groove with an opening angle of 70^∘. In this case, the walls of the groove match the {111}-facets of the cubic crystal.
In this work, we developed a lithography and etching procedure to create V-shaped grooves inside a 3C-SiC substrate. Electron-beam lithography is applied to create a structure with a width of 100 nm. Reactive-ion etching (RIE) is used to etch a V-shaped groove into the substrate. The RIE process is based on Sulfur hexafluoride to ensure a high lateral etch rate. Scanning electron microscopy (SEM) reveals that the walls are formed by {111}-facets of the cubic crystal. In addition, the first attempts to grow c-GaN on the pre-patterned substrates are discussed. The crystal quality is investigated by high-resolution X-ray diffraction and photoluminescence spectroscopy. The structures are further analyzed by SEM and atomic force microscopy.