Selective Area Growth of Cubic Gallium Nitride in Nanoscopic Silicon Dioxide Masks

Herein, the possibilities of nanoselective area growth (NSAG) of cubic gallium nitride on 3C-SiC/Si (001) pseudo substrates are studied. Growth is masked by SiO2 patterned with hole arrays and groove structures. Nanosphere lithography and block-copolymer lithography are employed to pattern holes with diameters of 130 and 17 nm, respectively. Electron beam lithography is used to pattern grooves. Patterns are transferred into SiO2 and 3C-SiC by reactive ion etching with CHF3/Ar and SF6 chemistry, correspondingly. It is possible to demonstrate phase pure nanoselective nucleation of c-GaN on and facets of 3C-SiC. Phase pure nucleation of cubic gallium nitride is confirmed by transmission electron microscopy measurements on the nanoscopic scale. A hexagonal fraction of 17.6% is achieved on the macroscopic scale measured by high-resolution X-ray diffraction (HRXRD), employing V-shaped grooves on 4 degrees miscut substrates. Furthermore, the possibility of coalescence after NSAG is demonstrated with the dominant cubic phase.