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

Abstract

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 <001> and <111> 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° miscut substrates. Furthermore, the possibility of coalescence after NSAG is demonstrated with the dominant cubic phase.