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Mikro- und Nanosysteme Prof. Dr. Christofer Hierold
http://www.micro.mavt.ethz.ch
Masters Thesis / Semester project
Biomimetic microhairs for zero-‐power MEMS actuators
Motivation Micro-‐Electro-‐Mechanical-‐Systems (MEMS) use actuators for a multitude of tasks like moving, gripping, switching, lifting and tilting of objects. Applications can be found in bioMEMS, micro-‐optics, microelectronics, microfluidics and many other fields. Actuators need some sort of energy to oper-‐ate and typically this energy is supplied in form of electric power. An electric current can for example be used to deform a piezoelectric material or to deform a bimetallic structure by resistive heating. In emerging energy harvesting applications for the Internet-‐of-‐Things (IOT) energy is a very limited resource. As a result, systems need to be as efficient as possible to work with the very small available energy budget. In this project, a zero-‐power actuator is de-‐veloped that mimics the behavior of mammal hair when exposed to temperature changes.
Figure 1: Bimetallic microhairs that rise and fall with ambient temperature changes
Approach Nature uses tiny muscles (arrector pili) at the base of each hair to erect it when the envi-‐ronmental temperature falls. We will replicate this effect by using artificial bimorph micro-‐hairs that can bend up or downwards with changing temperature. Hairs are fabricated in the cleanroom from two connected polymers with a large difference in CTE (coefficient of thermal expansion). Mechanical stress in the material will cause a deformation of the hairs as function of the temperature according to the bimetallic effect. Depending on the design of the structures, they can be used for a varie-‐ty of actuator applications. Task description Design of MEMS photolithography masks, cleanroom fabrication of microhairs in BRNC (IBM, Rüschlikon) and FIRST (CLA, ETHZ). Tes-‐ting and evaluation of the fabricated actua-‐tors for different applications. Learning opportunities You will learn how: 1. To design photolithography masks 2. Work in the cleanroom 3. Operate cleanroom equipment 4. To use experimental tools and charac-‐
terization techniques 5. Work independently and systematically 6. Write a good scientific report.
Contact: Moritz Thielen Micro and Nanosystems, CLA G11.2 Email: [email protected] Phone: +41 44 632 2522
2 mm