Design considerations of CMOS micro-heaters to directly synthesize carbon nanotubes for gas sensing applications

摘要

Compact and low cost gas sensors can be produced by growing Carbon Nanotubes (CNTs) as sensing material on a CMOS chip. Direct CNT synthesis on CMOS is possible by local resistive heating on suitable CMOS conductive layers. However, this synthesis process using thermal chemical vapor deposition requires near 900 °C temperature, which can compromise the functionalities of CMOS circuits. Therefore, CMOS micro-heaters have been modelled and simulated to investigate the achievability of the designs on actual chips. This paper will present the design considerations of the simulated CMOS micro-heaters, demonstrating how global heating of the microsystem can be avoided and mechanical integrity of the micro-heaters maintained. The required CMOS post-processing is outlined.