[19p-A402-1~14] 3.9 Terahertz technologies

▲ [19p-A402-4] Strain tuning in GaAsP MEMS beam resonators for terahertz bolometer applications

〇(M2)Boqi Qiu¹, Ya Zhang¹, Naomi Nagai¹, Kouichi Akahane², Kazuhiko Hirakawa^1,3 (1.IIS, Univ. of Tokyo, 2.NICT, 3.INQIE)

Keywords:terahertz bolometer, MEMS beam resonator, Strain tuning

We reported a room temperature, all electrical driving and detecting, very sensitive thermometer using a GaAs doubly clamped microelectromechanical (MEMS) beam resonator for bolometer applications. When the MEMS beam is heated by THz radiation, its resonance frequency is shifted by a temperature rise and the signal is detected by the piezoelectric effect. Increasing the quality factor (Q) of the mechanical resonance is advantageous for improving performance of the MEMS bolometer. Previously we reported that introduction of large tensile strain induced by lattice mismatch between GaAs_1-xP_x (x = 0.06) and GaAs improves the Q-factor of the MEMS resonators by 6 times, when compared with that of the unstrained GaAs resonators. However, since the MEMS beams become ‘hard’ with large tensile strain, the resonance frequency of GaAsP MEMS resonators also increased by several times, resulting in a significant decrease in the thermal responsivity of the MEMS resonators. In this work, we have introduced a small amount of tensile strain in the MEMS beam by tuning the ratio of phosphorus, achieved high Q-factor of MEMS resonator, and avoided the responsivity decrease.