A 4H-SiC Bipolar Technology for High-Temperature Integrated Circuits

Abstract

A 4H-SiC bipolar technology suitable for high-temperature integrated circuits is tested with two interconnect systems based on aluminum and platinum. Successful operation of low-voltage bipolar transistors and digital integrated circuits based on emitter coupled logic (ECL) is reported from 27°C up to 500°C for both the metallization systems. When operated on −15 V supply voltage, aluminum and platinum interconnect OR-NOR gates showed stable noise margins of about 1 V and asymmetric propagation delays of about 200 and 700 ns in the whole temperature range for both OR and NOR output. The performance of aluminum and platinum interconnects was evaluated by performing accelerated electromigration tests at 300°C with current density of about 1 MA/cm2 on contact chains consisting of 10 integrated resistors. Although in both cases the contact chains failed after less than one hour, different failure mechanisms were observed for the two metallization systems: electromigration for the aluminum system and poor step coverage and via filling for the platinum system.