Assembly Materials and Processes for High-Temperature Geothermal Electronic Modules

Geothermal well logging and instrumentation applications require high-temperature logging tools and sensors with long-term operation capability at 300
$^{\circ}{\rm C}$
. Advanced SiC technology has enabled high-temperature electronics. To build functional systems operating at high temperatures, an interconnection and packaging technology must be developed to interconnect SiC devices and passive components. Off-eutectic AuSn has been evaluated for SiC and passive component attachment to PtPdAu/Au thick film metallization on alumina substrates and on thick film dielectric. A functional SiC-based oscillator module was fabricated and tested to demonstrate the assembly technologies developed for 300
$^{\circ}{\rm C}$
applications.