This Small Business Innovation Research (SBIR) Phase I project addresses an approach to incorporate the advantages of SiC devices with the incumbent advantages of Si processing and circuit technology to form hybrid circuits which will enable advanced power conversion systems. The multi-kilowatt power loads handled by the processors leads to the generation of high thermal loads which must be be transported away from the active area of the devices. The hybrid circuits will be made by attaching SiC power devices to a revolutionary, highly-thermally-conductive hybrid substrate, and driving the power devices with Si circuits on the same chip so that the heat generated in the SiC devices can be efficiently carried away from the active area. This unique substrate is a Si-on-SiC hybrid wafer comprised of a very thin Si membrane (~1 micron) that has been sliced from a Si wafer and attached to a SiC wafer. <br/><br/>The general hybrid circuit technology being developed could be applied to both lower power systems (1-30kW) and higher power systems (30kW to MW systems), as well as RF systems from the kHz to GHz. The proposed planar hybrid circuits can lead to improved power conversion and inverter systems, as well as circuitry that could lead to improved computer processors. The hybrid wafers and devices will lead to decreased power consumption and waste heat in power systems critical to United States electricity grid and infrastructure.