[21p-A202-1~12] 3.8 Terahertz technologies (formerly 3.9)

△ [21p-A202-7] Uncooled terahertz bolometer by using a silicon-on-insulator (SOI) microelectromechanical-system(MEMS) resonator

〇Kazuki Ebata¹, Mirai Iimori¹, Morohashi Isao², Zyang Ya¹ (1.Tokyo Univ. of Agri.&Techno, 2.NICT)

Keywords:MEMS bolometer, SOI, terahertz

Microelectromechanical-system (MEMS) resonators are promising for realizing sensitive and fast terahertz (THz) sensors owing to their intrinsic high sensitivities. Previously, we have developed a THz bolometer with a GaAs doubly clamped MEMS resonator.The MEMS bolometer detects the incident THz light as a shift in the resonance frequency and works as a very sensitive THz sensor. However, owing to the interactions between THz wave and the optical phonons in GaAs material, there is a zero-sensitivity band at 7-10 THz, which prevents the use of MEMS bolometer in broadband THz spectroscopy measurements. In this research, we have developed an uncooled THz bolometer by using a silicon-on-insulator (SOI) MEMS resonator. High-resistivity silicon has a very flat transmission spectrum in THz and infrared frequency band, therefore, is very promising for realizing high sensitivity broadband THz sensors. We fabricated the structure of doubly clamped MEMS resonator whose beam has a geometry of 120×30×2.3μm³. The SOI MEMS resonator has a very high quality(Q)-factor of ~17000, which enables the sensitive detection of the shift in the resonance frequency. Furthermore, the thermal responsivity achieves ~26.5 /W, which is comparable with our previous GaAs MEMS bolometers. These results show that SOI MEMS resonators are promising for realizing high sensitivity, broadband THz sensors.