High Temperature Digital and Analogue Integrated Circuits in Silicon Carbide

Silicon Carbide devices are capable of operating as a semiconductor at high temperatures and this capability is being exploited today in discrete power components, bringing system advantages such as reduced cooling requirements. Therefore there is an emerging need for control ICs mounted on the same modules and being capable of operating at the same temperatures. In addition, several application areas are pushing electronics to higher temperatures, particularly sensors and interface devices required for aero engines and in deep hydrocarbon and geothermal drilling This paper discusses a developing CMOS manufacturing process using a 4H SiC substrate, which has been used to fabricate a range of simple logic and analogue circuits and is intended for power control and mixed signal sensor interface applications. Test circuits have been found to operate at up to 400 degrees C. The introduction of a floating capacitor structure to the process allows the use of switched capacitor techniques in mixed signal circuits operating over an extended temperature range.