STTR Phase I: Growth of 3C-SiC Substrates using High-Temperature Chemical Vapor Deposition

This Small Business Technology Transfer (STTR) Phase I project aims at developing new material growth technology for manufacturing semiconductor substrates of cubic 3C-SiC polytype for high-power, high-frequency, high-temperature, and high-radiation hardness military, space, and commercial applications. The new process for SiC epitaxial growth utilizes novel mechanisms of gas phase and surface reactions. These mechanisms are provided by using halo-carbon growth chemistry replacing the traditional propane-based system. Applied to homoepitaxial growth of the 4H-SiC polytype, the new growth method resulted in defect-free epilayers at temperatures as low as 1350C, which is much lower than what was considered possible for high-quality growth. Simultaneously, a drastic increase of the growth rate in comparison to the propane-based growth was achieved at regular for 4HsiC growth temperatures. The halo-carbon growth promises to resolve critical problems impeding 3C-SiC commercialization such as morphology degradation by unfavorable homogeneous reactions, lattice mismatch-related defect generation, and growth rate reduction by silicon vapor condensation. Commercial supply of wafers of 3C-SiC polytype is not available today. Growing efforts to develop and commercialize 3C-SiC technology in Japan and Europe may put the wide band gap industry in the US significantly behind in cost-efficiency of SiC electronics. This novel fabrication method offers a possibility of a strong competitive advantage. The potential for process scaling makes it possible to achieve large-diameter 3C wafers in less than 3 years. Use of Si substrates for 3C seed growth will ensure an estimated order of magnitude advantage in cost-to-diameter ratio in comparison to 4H and 6H-SiC wafers. Overcoming the price and wafer size limitations of the existing SiC technologies will significantly speed up commercial acceptance of high-power and high frequencySiC devices.