MSc thesis project proposal

High aspect ratio surface micro-machining using carbon nanotubes

Convential high-aspect ratio structures in microelectromechanical systems (MEMS) are made using bulk micro-machining, which requires KOH etching or deep reactive ion etching (DRIE). These kind of processes cost a lot of time, and waste much of the silicon. Furthermore, they have distinct limitations with regards to the aspect ratios which can be achieved. Surface micro-machining is a more elegant approach, which uses thin-film deposition to fabricate MEMS structures on top of Si substrate. However, it is not possible to create high-aspect ratio structures using thin-film deposition.

Carbon nanotubes (CNT) can be grown at extreme aspect ratios from only nm-thin metal catalyst by using chemical vapour deposition. This would allow the fabrication of high-aspect ratio structures on top of the wafer, by using CNT combined with SiN or SiC filling to improve the mechanical properties. This results in electrically conductive mechanical structures with the mechanical properties of the SiN or SiC filling material. These structures can be used to fabricate all kinds of novel MEMS actuators on the surface of a wafer, like micro-switches and resonators with unique electrical and mechanical properties.


The student will perform the fabrication in the Dimes cleanroom and will get training to use the equipment. The project will consist of the following tasks:
  • Design of surface actuator using the CNT and filler material
  • Fabrication of designed actuator
  • Characterisation of the actuator and publication at a conference or in a journal


Background in micro-electronics or microfabrication and basic knowledge of mechanics.

Contact Sten Vollebregt

Electronic Components, Technology and Materials Group

Department of Microelectronics

Last modified: 2016-02-25