Integration of PDMS-infiltrated CNTs and Si bulk-micromachining for monolithic physical sensors application

This study reports an improved approach to establish a batch-fabricated process to implement carbon nanotubes based monolithic physical sensors including pressure, acceleration, and temperature. The merits of the presented integration process are as follows: (1) the strain transference and electron thermal activation between nanotubes are improved by effectively infiltrating PDMS into the gaps of vertically-aligned CNTs forest; (2) PDMS with lower Young´s modulus (E~2MPa) was adopted as suspended structure to increase sensitivity of sensors; (3) the process is easily batch fabricated, and enables the integration of CNTs-PDMS and rigid Si structure. In application, the CNTs-based pressure sensor, accelerometer, and temperature sensor are implemented by the integration of PDMS-infiltration and Si bulk-micromachining process. Preliminary tests show that the sensitivity is significantly improved.