Microfabricated torsional actuator using self-aligned plastic deformation

We describe microfabricated torsional actuators that are made using self-aligned plastic deformation in a batch process. The microactuators are formed in single-crystal silicon and driven by vertical comb-drives. Structures have been built that resonate at frequencies between 1.90 and 5.33 kHz achieving scanning angles up to 19.2 degrees with driving voltages of 40 V/sub dc/ plus 13 V/sub ac/. After continuous testing of 5 billion cycles at the maximum scanning angle, there appears to be no observable degradation or fatigue of the plastically deformed silicon tors ion bars. We present measured results obtained with MEMS scanning mirrors; the actuators may be useful for many other MEMS applications.

[1]  J. Patel,et al.  Macroscopic Plastic Properties of Dislocation‐Free Germanium and Other Semiconductor Crystals. I. Yield Behavior , 1963 .

[2]  A. Evans,et al.  Polysilicon microstructures , 1991, [1991] Proceedings. IEEE Micro Electro Mechanical Systems.

[3]  Michael A. Huff,et al.  A threshold pressure switch utilizing plastic deformation of silicon , 1991, TRANSDUCERS '91: 1991 International Conference on Solid-State Sensors and Actuators. Digest of Technical Papers.

[4]  Khalil Najafi,et al.  Vertical comb array microactuators , 1995 .

[5]  Eui-Hyeok Yang,et al.  Microactuated self-assembling of 3D polysilicon structures with reshaping technology , 1997, Proceedings IEEE The Tenth Annual International Workshop on Micro Electro Mechanical Systems. An Investigation of Micro Structures, Sensors, Actuators, Machines and Robots.

[6]  Hongrui Jiang,et al.  Integrated polysilicon and DRIE bulk silicon micromachining for an electrostatic torsional actuator , 1999 .

[7]  Kam Y. Lau,et al.  A raster-scanning full-motion video display using polysilicon micromachined mirrors , 2000 .

[9]  Kristofer S. J. Pister,et al.  Torsional Micromirrors with Lateral Actuators , 2001 .

[10]  Mounting of Si-Chips with Plastically Bent Cantilevers , 2001 .

[11]  M. Wu,et al.  A scanning micromirror with angular comb drive actuation , 2002, Technical Digest. MEMS 2002 IEEE International Conference. Fifteenth IEEE International Conference on Micro Electro Mechanical Systems (Cat. No.02CH37266).