A vapor-liquid-solid mechanism for growing 3C-SiC single-domain layers on 6H-SiC(0001)

Growing device-quality 3C-SiC monocrystalline material is still an issue despite two decades of work dedicated to the subject. Using silicon as the substrate generates too many defects in the layers, owing to lattice mismatch, while it is very difficult to control the initial nucleation on an alpha-SiC substrate so that 60 degrees rotated domains are randomly formed. Herein, the elaboration of mono-orientated 3C-SiC layers on a 6H-SiC(0001) on-axis, Si face substrate using a vapor-liquid-solid mechanism is reported. This non-conventional approach for growing monocrystalline layers involves feeding a Ge-Si melt by a propane flux at a temperature ranging from 1250 to 1550 degrees C. We show that, by using this technique, the 3C-SiC material is almost always obtained on an hexagonal substrate, even if the crystal seed is oriented 8 degrees off-axis. Using on-axis 6H-SiC seeds and optimal growth conditions results in the reproducible deposition of single-domain 3C-SiC layers. A mechanism is proposed to clarify some aspects of this process.