[Zurück]

J. Sama, R. Jimenez-Diaz, J. Prades, O. Casals, F. Hernandez-Ramirez, S. Barth, A. Romano-Rodriquez:
"Nanowire Device Integration Assisted by FIBID and FEBID Contacting Process for Advanced Nanodevices";
Vortrag: MRS Spring Meeting 2013, San Francisco CA; 01.04.2013 - 05.04.2013; in: "MRS 2013 Spring Meeting", (2013).

Nanowires have been among the most promising nanostructures because of the potential applications in electronic devices, and due to their high surface volume ratio [1]. One of the most important challenges in fabricating nanodevices is the integration of nanostructures in a reliable and reproducible manufacturing process. Contacting nanowires is a key issue in several applications in which the nanowire acts as functional material, as gas sensors or UV photodetectors based on single nanowire. Integration of these materials into a nanodevice, which requires manipulation and fabrication of contacts in specific locations, is still limited. This work will report several activities that we have carried out on the fabrication of contacts to nanowires by Focused Ion and Focused Electron Beam Induced Deposition (FIBID and FEBID, respectively) with the aim of producing low power advanced gas nanosensors.
Metal oxide materials behave as chemiresistors whose resistance value depends on the presence of gas in the surrounding atmosphere. The resistance change is due to reactions of the gases with the surface of the metal oxide. This principle has been used for the development of commercial devices, a market in which micro and nanostructures will provide enhanced sensing effects due to the high surface to volume ratio, consequence of the 1D shape [2].
For the here presented experiments, monocrystalline tin dioxide nanowires were synthesized by chemical vapor deposition (CVD), using the molecular precursor [Sn(OtBu)4] [3]. Nanowires are pulled off of the substrate, and dispersed on a solvent (ethyleneglycol or isopropanol). A droplet is deposited onto an isolating substrate, typically Si/SiO2, with interdigitated microelectrodes made by photolithography. The sample is introduced in a dual beam SEM / FIB equipped with a Pt injector (precursor: (CH3)3CH3C5H4Pt)), where one nanowire is selected and contacted to the prepatterned electrodes employing the local decomposition of the precursor gas either by the electron or the ion beams. In the here presented methodology both beams are used on a sequential bases to optimize the deposition process, the electrical properties of the deposited layers and to avoid structural damage to the nanomaterial. This methodology is a modification of that presented by the authors for conventional silicon substrates [4].
This contribution attempts to critically discuss the fabrication strategy and parameters, their impact on the electrical behavior of the fabricated nanostructures, the fabrication of operative nanodevices and the capabilities and limitations of the here presented methodology.
[1] X. Huang et al, Sensors Actuators B (2007) 122 659.
[2] P.T. Moseley et al, Solid State Gas Sensors, (1987) Adam Hilger.
[3] S. Mathur et al, Small 1 (2005) 713.
[4] F. Hernandez-Ramirez et al, Nanotechnol. (2006) 17 5577.

http://www.mrs.org/s13-program-t/