position control, MEMS, thermal actuator


Feedback control of MEMS devices has the potential to significantly improve device performance and reliability. One of the main obstacles to its broader use is the small number of on-chip sensing options available to MEMS designers. A method of using integrated piezoresistive sensing is proposed and demonstrated as another option. Integrated piezoresistive sensing utilizes the inherent piezoresistive property of polycrystalline silicon from which many MEMS devices are fabricated. As compliant MEMS structure’s flex to perform their functions, their resistance changes. That resistance change can be used to transduce the structures’ deflection into an electrical signal. The piezoresistive microdisplacement transducer (PMT) is a demonstration structure that uses integrated piezoresistive sensing to monitor the output displacement of a thermomechanical inplane microactuator (TIM). Using the PMT as a feedback sensor for closed-loop control of the TIM provided excellent tracking with no evident steady-state error, maintained the positioning resolution to ±29 nm or less, and increased the robustness of the system such that it was insensitive to significant damage.

Original Publication Citation

Messenger R., Aten, Q., McLain, T., and Howell, L. Piezoresistive Feedback Control of a MEMS Thermal Actuator, Journal of Microelectromechanical Systems, vol 18, no. 6, pp. 1267-1278, 2009.

Document Type

Peer-Reviewed Article

Publication Date


Permanent URL






Ira A. Fulton College of Engineering and Technology


Mechanical Engineering