SOI MEMS resonators with electrical driving and readout for uncooled terahertz sensing applications

MEMS resonator-based detectors have emerged as promising candidates for terahertz (THz) sensing applications due to their high sensitivity, rapid response, and room-temperature operation. This study demonstrates uncooled THz bolometric detection using doubly clamped MEMS beam resonators fabricated on commercial silicon-on-insulator (SOI) substrates. SOI MEMS bolometers leverage thermally induced internal strain to produce significant resonance frequency shifts, achieving impressive sensitivity and detection speeds, significantly surpassing traditional pyroelectric sensors. Moreover, SOI MEMS bolometer employs all electrical driving and readout method, achieved by using piezoresistive effect of Si material. Enhanced THz collection efficiency was attained by mounting MEMS bolometers on hyper-hemispherical Si lenses, with alignment optimization via a 1.5 μm laser and an infrared microscopy. Resonance frequency shift is observed by irradiating the MEMS beam with a weak, broadband THz source from a FTIR. Spectroscopic measurements demonstrate the superior broadband capability of SOI MEMS bolometer compared to previous developed GaAs-based MEMS bolometer, indicating its considerable potential in advanced THz sensing applications.