Photomask-based integration process of low-defect suspended carbon nanotubes into SOI MEMS

A fully-developed photomask-based integration process is reported. The process can integrate suspended carbon nanotubes (CNTs) into micro-structures on silicon-on-insulator chips. The process features batch-compatible fabrication and post-growth metallization of suspended CNTs, which has never been demonstrated by any other processes. The post-growth metallization avoids deterioration of the metals at the elevated CNT growth temperature and enables mechanically robust double-clamped configuration. Two key steps ensure a significant reduction of the risk for damage or contamination of the CNTs during post-growth processing. SiO 2 bridges were fabricated to physically support CNTs during the wet processing, and a protective Al 2 O 3 layer (∼40 nm) was deposited to prevent resist contamination during lithography. The combination of these two steps enables the removal of the unprotected suspended segments of unwanted CNTs by oxygen plasma ashing, improvin...

Shih-Wei Lee, Matthias Muoth and Christofer Hierold

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