Single-crystalline (100) Ge networks on insulators by rapid-melting growth along hexagonal mesh-pattern

Single-crystalline-Ge (c-Ge) networks on insulator films formed on Si substrates are essential for integrating high-speed and multifunctional devices onto the Si-platform. Rapid-melting-growth of mesh-patterned amorphous-Ge is examined over large areas (500×250 μ m²). For squared-mesh-pattern, polycrystalline-Ge forms throughout most of the mesh, though c-Ge is obtained near (<100 μm) Si-seed. Based on the consideration of geometric-effects, mesh-patterns are changed to hexagonal. This realizes c-Ge networks over the entire insulator area. These results indicate that Ge growth initiated from Si-seed propagates laterally over the hexagonal-mesh- pattern though bending and branching. These unique c-Ge-networks on insulators facilitate Ge-based advanced-devices on the Si-platform.