SIC EPITAXIAL LAYERS FOR ULTRA-HIGH VOLTAGE BIPOLAR DEVICES

This program is focused on growth of thick low doped Silicon Carbide epitaxial layers suitable for ultra-high voltage (10-15 kV) SiC bipolar power devices using improved epitaxial growth chemistries and reactor design. This Phase II STTR program will focus on extending the growth rates achieved in Phase I, and to realize epitaxial layers that alleviate VF drift in SiC bipolar devices. Reactor design and growth chemistries play a key role in the cost and quality of epitaxial layers. Traditional cold-wall epitaxial reactors cannot sustain high enough epitaxial growth rates without severe degradation in layer quality due to the formation of silicon droplets and other defects. Contemporary hot-wall epitaxial reactors may achieve a high epitaxial growth rate, but suffer from prohibitively high running and maintenance costs. By using a custom reactor design, the high temperature gradients will be reduced. Novel growth chemistries will be employed that increase the growth rate and widen the "growth window". Reduced epitaxial growth temperature is expected to allow the production of SiC epitaxial layers at a fraction of the cost of existing layers. This technology will enable devices with ratings that are relevant for power distribution and directed energy weapon systems of next generation naval combatants.