A Fast, Large-Stroke Electrothermal MEMS Mirror Based on Cu/W Bimorph

作者：Zhang Xiaoyang; Zhou Liang; Xie Huikai^*

来源：Micromachines, 2015, 6(12): 1876-1889.

DOI：10.3390/mi6121460

• microelectromechanical systems (MEMS) mirror
• electrothermal actuation
• Cu/W bimorph
• lateral-shift-free (LSF)
• vertical scan
• multimorph frame
• large range
• fast response
• backside release

This paper reports a large-range electrothermal bimorph microelectromechanical systems (MEMS) mirror with fast thermal response. The actuator of the MEMS mirror is made of three segments of Cu/W bimorphs for lateral shift cancelation and two segments of multimorph beams for obtaining large vertical displacement from the angular motion of the bimorphs. The W layer is also used as the embedded heater. The silicon underneath the entire actuator is completely removed using a unique backside deep-reactive-ion-etching DRIE release process, leading to improved thermal response speed and front-side mirror surface protection. This MEMS mirror can perform both piston and tip-tilt motion. The mirror generates large pure vertical displacement up to 320 m at only 3 V with a power consumption of 56 mW for each actuator. The maximum optical scan angle achieved is +/- 18 degrees at 3 V. The measured thermal response time is 15.4 ms and the mechanical resonances of piston and tip-tilt modes are 550 Hz and 832 Hz, respectively.

• 出版日期2015-12