Enhanced thermal sensitivity of MEMS bolometers integrated with two-dimensional phononic crystals

TL;DR

This study demonstrates that integrating two-dimensional phononic crystals into MEMS bolometers significantly enhances their thermal sensitivity by reducing thermal conductance and heat capacitance, with minimal impact on operational bandwidth.

Contribution

The paper introduces a novel integration of 2D phononic crystals into MEMS bolometers to improve thermal sensitivity without compromising bandwidth.

Findings

Thermal sensitivity increased by 2-3 times with PnC integration.

Thermal decay time increased by only 30-40%.

Thermal conductance reduction achieved without significant bandwidth loss.

Abstract

We have fabricated two-dimensional phononic crystal (PnC) structures on GaAs doubly-clamped microelectromechanical system (MEMS) beam resonators to modulate their thermal properties. Owing to the reduction in the thermal conductance of the MEMS beams by introducing the PnC structures, the MEMS bolometers with the PnC structures show 2-3 times larger thermal sensitivities than the unpatterned reference sample. Furthermore, since the heat capacitance of the MEMS beams is also reduced by introducing the PnCs, the thermal decay time of the patterned MEMS beams is increased only by about 30-40 %, demonstrating the effectiveness of the PnCs for enhancing the thermal sensitivities of bolometers without significantly deteriorating their operation bandwidths.