Agenda

Microelectronics colloquium

A SiC-carbon nanotube composite for MEMS

Sten Vollebregt

A SiC-carbon nanotube composite for MEMS

Silicon carbide (SiC) is a promising material for MEMS devices, especially for those aiming at harsh environment applications. However, the lack of a proper bulk fabrication process is a factor that impedes the development of SiC MEMS. Here, we propose to use an array of vertically aligned carbon nanotubes (CNT) reinforced by amorphous SiC as an alternative for high aspect ratio (HAR) SiC-based MEMS fabrication. We found that the CNT dominates the electrical properties of the composite. In contrast, the mechanical properties can be tuned over 3 orders of magnitude by varying the thickness of the a-SiC filler. Two different working devices were successfully fabricated and tested at elevated temperatures using this approach: a chevron-shaped thermal actuator and a capacitive accelerometer. Finally, we have also characterised the mechanical properties of the composite up to 900C and shown that its Young modulus does not change significantly over this range.

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