[10p-Z24-1~16] 3.9 Terahertz technologies

▲ [10p-Z24-6] GaAs-based MEMS terahertz bolometers fabricated on high-resistivity Si substrates using wafer bonding technique

〇(D)Tianye Niu¹, Natalia Morais², Boqi Qiu¹, Naomi Nagai¹, Ya Zhang³, Yasuhiko Arakawa², Kazuhiko Hirakawa^1,2 (1.IIS, Univ. of Tokyo, 2.INQIE, Univ. of Tokyo, 3.TUAT)

Keywords:terahertz, MEMS, wafer bonding

We proposed and realized a room-temperature operated, all electrically driving and detecting, sensitive and fast thermometer structure using a doubly clamped microelectromechanical (MEMS) resonator for bolometer applications. The MEMS detects the shift in the resonance frequency caused by heating and works as a very sensitive thermometer. However, since THz radiation is absorbed/reflected in the thick GaAs substrate, the responsivity spectrum of the MEMS bolometer is strongly affected by the phonon properties in GaAs and, in particular, loses its sensitivity in the Reststrahlen band, which is not suitable for detector applications. To get around this problem, here, we use the wafer bonding technique to make the MEMS bolometer on high-resistivity Si substrates. The wafer-bonded MEMS sample shows a large responsivity even in the Reststrahlen band of GaAs, where the responsivity vanishes in the standard MEMS bolometers fabricated on GaAs substrates. The wafer bonded samples successfully filled the responsivity gap in the standard MEMS bolometer and it becomes a very good candidate for far-infrared detection.