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DS: Fachverband Dünne Schichten

DS 11: Focus Session: Sensoric Micro and Nano-systems I

DS 11.9: Invited Talk

Tuesday, April 1, 2014, 12:15–12:45, CHE 89

Integration of individual SWCNTs into field-effect transistor-based sensors — •Miroslav Haluska, Wei Liu, Kiran Chikkadi, Matthias Muoth, Tobias Suss, Stuart Truax, Cosmin Roman, and Chrisofer Hierold — Micro- and Nanosystems, ETH Zurich, Tannenstrasse 3, 8092 Zurich, Switzerland

Sensor demonstrators based on single-walled carbon nanotubes (SWCNTs) have shown very promising performance, including high sensitivity, low detection limits, and ultra-low power consumption. In this presentation, we focus on sensors integrating individual SWCNTs in a field effect transistor (FET). Such carbon nanotube FETs (CNFETs) may be used for different sensor applications, e.g. NO2 gas sensors, pressure sensors, or mechanically resonating transducers. The electrical characteristics of these devices exhibit unpredictable device-to-device variations that cannot be explained solely by the different properties of the incorporated SWCNTs. The device fabrication processes and a choice of materials coming into contact with the SWCNTs can also affect the CNFET characteristics by altering the nanotube and/or the interface properties. To identify and optimize the most critical device fabrication steps, we performed a series of monitoring measurements at different stages of the fabrication process. The results we have obtained from improved nanotube integration processes, including the utilization of a temporary nanotube protection layer, give us optimistic expectations for the utilization of SWCNTs in future sensor devices. The improvements in particular include the decrease of electrical contact resistances and narrowing of Ids-Vg hysteresis widths.