Micro Clean RoomStaff: Sébastien GAUTHIER, Laurent GUIRAUD, David MARTROU
Exchanging energy, orders or information with a molecule require a specific fabrication technology to master the detail interactions of a single molecule with a few electrodes, tip apex or a dielectric wave guides. In most of the case the interaction must be master with a length scale well below 0.1 nm that is at the atomic scale. This is for example the case of the electronic interaction between a molecular wire and its interconnection pads. Here, the overlap between the molecular orbital of the end group of the molecule dedicated to the contact and the surface orbital at the end of the pad will vary exponentially with distance in the 0.05nm range. At the same time any atomic defects or disorder at the end of the electrode will modify this overlap and consequently the contact conductance of the molecular wire. This is also the case in molecular mechanics. When a molecule explores a surface, its legs, wheels…are adsorbed on the surface. Any atomic defect or atomic steps meet along the surface by the itinerant molecule will influence its intramolecular mechanics. So an extreme care must be taken in the preparation of the surface, in the construction of the contacting electrodes, of the tip apex… Many of the now standard nano-lithography techniques like e-beam or nano-imprint are not compatible with those extreme cleanness requirements at the surface of a solid to construct atomically precise interconnects. The GNS has launch a large instrumentation and surface science program for the development of a new atom technology, sometimes called “picotechnology”, expending “nanotechnology” deep in the bottom.
Picture taken outside of its UHV chamber of the Micro Clean RoomThe Micro Clean Room tool was developped in order to to establish planar electrical contacts with interconnections from nanoscale to a macroscopic circuit for measuring electrical properties of nanoobjects such as single molecule. The micro clean room is the end part of the DUF equipment. This project started in 2003 and is now fully completed. The Micro Clean Rom is implemented on a UHV OMICRON STM/AFM head modified to add the different tools, namely: 1. A flexural-hinge guided (XY) nanopositioner stage (100 µm x 100 µm, repeatability 5 nm) with a closed loop control based on capacitive sensors, 2. An evaporation system highly collimated on the cantilever to do the nanostencils deposition , 3. A (XYZ) positioning system for a metallic microcantilever probes array for electrical measurements on the sample , 4. An optical microscope to control the positioning of these microcantilever probes.
FIB- Erik Dujardin