1. Investigation of Multi-Layer Actuation Carlos R. Jimenez. California State Polytechnic University, Pomona. Electrical Engineering, Fall 2006 Faculty Mentor: Professor Andrei Shkel. Graduate Student Mentors: Max Perez, Adam R. Schofield. Department of Mechanical Aerospace Engineering. 08-30-2005

2. © C. Jimenez 2005, IM-SURE Motivations for out of plane actuation. Currently fabricated X-Y axis gyroscope driven by in-plane actuation. Desired X-Y-Z axis gyroscopes driven by in-plane and out-of- plane actuation. X Y sense direction Y Z X Driving direction Additional Sense capabilities

3. © C. Jimenez 2005, IM-SURE Out of Plane Actuation has a wide range of applications MEMS micro mirrors For optical switching. X-Y-Z Gyroscopes for the aerospace and automotive industry.

4. © C. Jimenez 2005, IM-SURE How are lateral combs actuated? Regular lateral combs for in- plane actuation driven by an AC voltage signal. Experimental concept for out-of- plane actuation driven by an AC voltage signal. VoVo +Vo-+Vo- t VoVo +Vo-+Vo- t

5. © C. Jimenez 2005, IM-SURE Motivations on using offset combs for out-of-plain actuation vs. parallel plates. Limitations when fabricating structures in Silicon- On-Insulator for out-of-plane actuations. Si Electrode V SiO 2 Unfortunately current fabricating techniques do not allow placing an electrode under a microstructure.

6. © C. Jimenez 2005, IM-SURE Target objectives for the research. Model various lateral comb architectures in Finite Element Analysis Software along with MATLAB. Design fabrication techniques to achieve lateral combs with different heights. Fabricate test structures to observe the deepness differences in the combs. Attempt to characterize structures.

7. © C. Jimenez 2005, IM-SURE Modeling Results contd.. Force in the Z direction Vs Height of Ground Comb. Changing Height 0-70um Constant 70 um

8. © C. Jimenez 2005, IM-SURE Modeling Results contd.. Force in the Z Direction Vs. Potential across Offset Combs Ground Variable Potential From 0 to 100V

9. © C. Jimenez 2005, IM-SURE Modeling Contd.. Out of Plane Force Vs. Comb Displacement. Displacement. Force becomes Negative after A 25um rise. -1.4e-12 N/um levitated

10. © C. Jimenez 2005, IM-SURE Fabrication parameters for force Maximization Sensitivity Analysis from the standard model. Standard@35um Tests: 15, 35, & 55um Standard Gap@10um Tests: 5,10 & 15 um Standard Gap @10um. Tests: 5, 10 & 15um

11. © C. Jimenez 2005, IM-SURE Designing test structures Making and evaluating masks. First approach: Opaque combs were thought to partially protect combs from UV light when exposed. Second approach: Create Structures with a two mask deposition. This mask was not successful for its Unexpected roughness Successful mask with 250um. resolution Smooth mask used to fabricate the structure

12. © C. Jimenez 2005, IM-SURE Manufacturing devices Lithography and etch for two mask process. Apply a thick layer of Photo-Resist. Protect the high combs with a first mask and develop the wafer. Hard Bake the wafer. Apply a thin layer of Photo-resist. Protect all combs with a second mask and develop again Deep etch for 90 minutes Si Deep etch for 45 more minutes.

13. © C. Jimenez 2005, IM-SURE Manufacturing Results Evaluating the etching process Despite the significant height decrease, the final etch was not evenly across the exposed combs. A Dektek 3 surface profiler was used to estimate the roughness on the small comb surfaces. Very rough

14. © C. Jimenez 2005, IM-SURE Pre-Characterization Isolating the Moving Structure Between the combs we deposited Sylgard182, an elastomer with flexible and isolating properties. Three days after, the elastomer cured, giving the possibility for electrical isolation. The Characterization of the test device was started but not fully completed.

15. © C. Jimenez 2005, IM-SURE How likely are offset combs to lift a structure? Standard in-plane vs. out-of plane forces.

16. © C. Jimenez 2005, IM-SURE Full MEMS experience. 2.Concept. 3.Modeling 4.Design Layout 6.Characterization 1.Idea 5.Fabrication

17. © C. Jimenez 2005, IM-SURE Acknowledgments Thanks to: Faculty Mentor: Prof. Andrei Shkel Graduate Student Mentors: Max Perez, Adam Schofield. Lab: Jesper Eklund, Max Perez, Adam R. Schofield, Alexander Trusov, Chandra S. Tupelly. IM SURE: Said Shokair. Calit2: Goran Matijasevic. Funded by: *National Science Foundation (NSF). *Undergraduate Research Opportunity Program (UROP).

18. © C. Jimenez 2005, IM-SURE Questions?

19. © C. Jimenez 2005, IM-SURE