Contoured thermal V-beam actuator with improved temperature uniformity

Abstract

This paper presents a new design of a contoured thermal V-beam actuator having a more uniform temperature distribution over its length. It has widened segments on both sides, symmetrically placed around the actuator tip in the centre. The chosen fabrication process allows the shape of the polysilicon heater element to deviate from the actual actuator geometry. A modified contoured thermal V-beam actuator with a uniform heater cross-section along the actuator length is designed, fabricated, tested and compared to both a conventional thermal V-beam actuator and a contoured thermal V-beam actuator in which the heater geometry follows the geometry of the underlying structure. The improved actuator is electrically equal to the conventional V-beam actuator, but thermally and mechanically equal to the contoured V-beam actuator, which has proven to be very advantageous. A more uniform temperature distribution along the actuator length is achieved, allowing for a larger overall thermal expansion and therefore also a higher deflection at the same maximum temperature. In combination with a higher actuator stiffness compared to the conventional actuator the output work that can be obtained is significantly increased at the expense of only a slightly larger chip area. Compared to the contoured actuator, the output work of the improved contoured actuator has increased with almost 50%, without increase of required input power.