Surface micromachined linear thermal microactuator

A linear thermal actuator based on controlled resistive heating of a suspended, micromachined, polysilicon (and silicon carbide) serpentine has been demonstrated. Maximum linear displacements of 1.5 mu m were measured for a polysilicon serpentine microbridge consisting of six bars (500 mu m*10 mu m*2 mu m). These displacements occur when sections of the micro-serpentine have been resistively heated to an average temperature change Delta T of 200 K to 500 K. Although this approach to linear actuation produces only small displacements, these thermally generated forces are significantly larger than those which can be obtained by electrostatic actuation methods. This novel thermal microactuator design is compatible with current IC processing techniques and may have applications for precision linear positioning or mechanical switching.<>