Direct Integration of Carbon Nanotubes on Micro Gas Sensing Platforms

This communication reports on the localized growth of carbon nanotubes (CNTs) on the surface of micro-hotplates with integrated transducing electrodes. A catalytic thermal CVD process has been adapted to grow CNTs by only using the heat provided by the integrated heater. Few groups have already reported such a CNT growth on a micro-heater but our work differs on the point that we use a classical micro-hotplate to locally grow CNTs on integrated electrodes to electrically contact the CNTs. These platforms are fabricated using conventional IC and specific microsystem processes and are used in resistive metal oxide gas sensors. They can reach within milliseconds and at low power a temperature up to 900degC. The influence of the catalyst, methane flow, and temperature cycles on the growth of CNT was investigated. Different strategies were investigated to get the electrical connection between the CNTs and the platinum electrodes. The concept proposed is to replace the metal-oxide layer by a network of gas-sensitive CNT integrated onto the micro gas sensing platform.