3C-SiC has the lowest (2.3 eV) and shows the highest and saturation velocity, because of reduced phonon scattering resulting from a higher symmetry , , , . Furthermore, 3C-SiC is the most thermodynamically stable polytype meaning it can be grown at lower temperatures (i.e. below 1500 °C) . The of 3C-SiC at lower temperature is both a limitation and an advantage for 3C-SiC development. The reduced thermal budget required for 3C-SiC growth limits the development of reliable 3C-SiC bulk growth technology, which requires faster growth of subsequent homo-epitaxial layers in order to obtain device-grade 3C-SiC . The lack of high quality 3C-SiC substrates forces 3C-SiC to be grown on different substrates hetero-epitaxially. Hetero-epitaxial growth of 3C-SiC on hexagonal polytypes (both 6H- and 4H-SiC) has been attempted to be optimized , , , but the manufacturing costs are too high.
Developing a technology based on 3C-SiC hetero-epitaxy is motivated mainly by the possibility that such a system reduces the cost for production of wide band-gap materials. In the past few decades, the scientific efforts devoted to the manufacturing of 4H-SiC technology concentrated mainly in developing larger area seeds for substrates and high-purity electronic-grade epitaxy Nonetheless, relevant drawbacks remain such as the cost for material production and the viability of reliable and efficient electronics devices, e.g. . A comparison of the estimated production cost of SiC for applications shows that a 6 µm thick 3C-SiC epitaxial layer grown on a 8 in. would cost about 2 $/cm2 compared to 20 $/cm2 for a similar 4H-SiC homo-epitaxial layer. Of course, 4H-SiC homo-epitaxy is a more mature technology and the resulting crystals show a much higher purity. Indeed, 3C-SiC crystals grown on Si exhibit large stress in the system, as a consequence of the poor compliance between the substrate and the epitaxy resulting in lower material quality and not processable bowed wafers. On the other hand, 8 in. 4H-SiC development is still in the early stages.
