A CMOS integrated thermal sensor based on Single-Walled Carbon Nanotubes

This paper presents a fully functional thermal sensor based on Single-Walled Carbon Nanotubes (SWNTs) integrated with CMOS interface circuitry utilizing die-level post-CMOS processing. The SWNTs are incorporated on the CMOS circuitry by utilizing a low temperature Dielectrophoretic (DEP) assembly process, which includes a pretreatment of an electroless zincation to prepare the top metal layer of the CMOS chip for assembly. The entire sensor system is next encapsulated with a parylene-C layer for improving the contacts between the SWNTs and the electrodes. The SWNTs were assembled as the gain element of an integrated inverting amplifier circuit. I-V measurements indicate that the temperature coefficient of resistance for the SWNT-based thermal sensor is -0.40% over a temperature range from 25degC to 105degC. The indirect measurement of the TC from the AC gain of the amplifier displayed a temperature coefficient of -0.33% over the same temperature range. This is the first successful demonstration of a fully functional SWNT-based thermal sensor on CMOS and the entire concept can be easily extended to other nanostructures for numerous other applications.