Technique of creation of Si/SiO2/metal structures using swift heavy ion tracks |
Creation of latent tracks by Swift Heavy Ions (SHI)
The interaction of high energy ions with matter are formed disordered region in the matter. The degree of damage depend on the type and energy irradiating ion. At low energies of irradiation are formed unit defects in the surficial region. At intermediate energies are formed elongated defect region. At high energies are formed latent tracks on the entire thickness of the polymer film.
On slides below are shown accelerators for irradiation of the polymer by swift heavy ions.
Accelerator centre "GSI Helmholtzzentrum fuer Schwerionenforshung" (Darmstadt, Germany):
Etching of SHI tracks
Nanopores in polymer films after etching of latent tracks. Examples of nanopores for different types of polymer films: polyethylene terephthalate (PET) and polyimide (PI). The size and shape of pores have set up by parameters of irradiation and etching. Irradiation Ar, 1 GeV => etching NaOH, 45 oC => cylindrical tracks (pores). Irradiation Kr, 350 MeV => etching NaOCl, 70 oC => hyperbolic tracks (pores).
Advantages of the technology tracks of swift heavy ions in a flexible polymer films:
SHI track can be transformed into a pore, if the etching rate along the track (VT) is larger than the bulk etching rate (VB), which is a rate of etching of unirradiated material beyond the SHI track area. The VT/VB ratio depends of the density of radiation damage in a latent track. Therefore a selective etching procedure of a latent track is possible if VT/VB > 1. Moreover, this parameter determines a form of the etched track.
Time characteristics of parameters of forming pores.
Pores obtained as a result of the etching.
Metals (Ni, Cu) deposition in pores
Depending on the method of filling nanopores can create different types of nanostructures. Examples of filled nanopores:
Deposition of metals in pores has been carried out electrochemically from a liquid phase (electrodeposition). This method makes it possible to vary such structural parameters as cluster dimensions, layer thickness, sequence of layers and morphology of deposited material by means of a change of deposition time as well as a potential on the electrode.
Specific characteristics of the method:
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