Evolutionary growth of microscale single crystalline GaN on an amorphous layer by the combination of MBE and MOCVD

To integrate multiple functional devices on a chip, advances in epitaxial growth on heterosubstances are required. We developed a method of combined epitaxial growth using molecular beam epitaxy (MBE) and metal-organic chemical vapor deposition (MOCVD) as one approach to achieve an epitaxial layer on an amorphous substrate. This two-stage combined growth can be used to grow binary gallium nitride (GaN) on any thermally durable substance. The first MBE growth step provided effective nucleation with uniform morphology. Meanwhile, the second MOCVD growth step resulted in improved crystalline quality. Detailed analysis of grain-to-grain and layer-to-layer interfaces was performed with high-resolution transmission electron microscopy (TEM) characterization. This study gives a deep understanding of the growth behavior, thereby supporting the generation of perfect single crystalline GaN, enabling the realization of optoelectronic GaN-based devices on an amorphous layer.