Thick film hybrid packaging techniques for 500/spl deg/C operation

A source follower circuit was constructed on a custom alumina substrate using thick film hybrid techniques and 4H-SiC JFETs. The circuit is intended for long term operation at a temperature of 300/spl deg/C. For this reason, the various components of the circuit assembly (wire bonds, resistors, die attach, substrate metalization) have undergone accelerated reliability testing at an elevated temperature of 500/spl deg/C. These experiments have confirmed the operation of SiC based circuits at a temperature of 300/spl deg/C, but also, prove the plausibility of future circuits operating in the 500/spl deg/C range.