High energy ion beam irradiation of polymers for electronic applications (original) (raw)
Related papers
HEAVY ION TRACKS IN POLYMERS AND THEIR APPLICATIONS
Heavy ion tracks in polymers offers a tremendous number of interesting applications in various fields of science and technology. The ion track filters produced by these irradiated polymers have advantage over conventional filters due to its simplicity, small geometry, permanent maintenance of the nuclear records and well-defined pore size. We report here some applications of ion track filters, in micro hydro dynamical flow studies, conduction of bacteria and blood cells, development of metal and metal–semiconductor microstructures and nanostructures. These micro/ nano wires have huge potential for their use as biosensors, field emission studies etc. Nano wires based sensors can detect diseases in blood samples.
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 1991
The keV-MeV ion irradiation of polymers produces deep changes in their physical and chemical properties associated with the breaking and rearrangement of original bonds. The modification of chain structure occurs within a well defined ion fluence range which depends on the ion linear energy transfer as well as on the target parameters. At low ion fluences (≈1014 ions/cm2) crosslinks between chains and chain-scissions are detected with a chemical yield in the range 0.05–0.3, depending on the ion mass. With increasing ion fluence (1015 ions/cm 2) the original polymer structure is heavily modified and the irradiated films exhibit properties close to those of hydrogenated amorphous carbon. At very high fluences (≈1016 ions/cm 2) graphitization of the material occurs.
Ion implantation of polymers: formation of nanoparticulate materials
2012
The current paper presents a state-of-the-art review in the field of ion implantation of polymers. Numerous published studies of polymers modified by ion beams are analysed. General aspects of ion stopping, latent track formation and changes of structure and composition of organic materials are discussed. Related to that, the effects of radiothermolysis, degassing and carbonisation are considered. Specificity of depth distributions of implanted into polymers impurities is analysed and the case of high-fluence implantation is emphasised. Within rather broad topic of ion bombardment, the focus is put on the low-energy implantation of metal ions causing the nucleation and growth of nanoparticles in the shallow polymer layers. Electrical, optical and magnetic properties of metal/polymer composites are under the discussion and the approaches towards practical applications are overviewed.
Track size and track structure in polymer irradiated by heavy ions
The structure of latent tracks in polyethylene terephthalate (PET) was studied using chemical etching combined with a conductometric technique. Polymer samples were irradiated with Ar, Kr, Xe, Au, and U ions with energies in the range of 1 to 11.6 MeV/u. The etching kinetics of the tracks was investigated in the radii range 0±100 nm. The highly damaged track core manifests itself on the etching curves as a zone where the etch rate changes dramatically and reaches its minimum at a radius of a few nm. It was found that the track core radius is approximately proportional to (dE/ dx) 0X55 . The track core is surrounded by a halo. In the track halo the etching proceeds at a rate that slowly increases approaching a constant value. Cross linking of macromolecules causes reduction of the etch rate in the halo which extends up to distances exceeding 100 nm in the case of the heaviest ions. Measurable change of the etch rate at such large radii could not be predicted from the shape of the calculated spatial distributions of energy dissipated in tracks. Obviously, formation of the extended track halo is in¯uenced by the diusion of active intermediates from the track core to the polymer bulk. Ó 0168-583X/98/$ ± see front matter Ó 1998 Elsevier Science B.V. All rights reserved. PII: S 0 1 6 8 -5 8 3 X ( 9 8 ) 0 0 4 4 5 -5
Ion beam effects in polymer films: Structure evolution of the implanted layer
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 1997
Thin films of polyethylene, polyamide-6 and cellulose implanted with 100 keV B+, Nf and Sb+ ions to the fluences of 10'3-10'7 cmv2 were investigated using RBS and NDP techniques as well as IR, UV-visible and EPR spectroscopies. The peculiarities of the depth distribution of implanted species and the origin of the processes responsible for modification of the structural, optical and paramagnetic properties of polymers are discussed with consideration for two major reactions occurring in the implanted layer: (i) oxidation of the radiation-damaged polymer that predominates at moderate doses; (ii) clusterization of radiation defects with the formation of carbon-enriched domains ("drops") which can overlap at high ion fluences yielding the network of conjugated carbon structures.
Compositional and structural alterations of polymers under low-to-medium-energy ion implantation
2005
Numerous studies of polymers modified by low-to-medium-energy ion beams are generalised. The accent is put on ion stopping in a polymer matrix, latent track formation and on complex process of polymer degradation. Main trends in the changes of the structure and composition of the polymers as a function of implantation conditions are discussed. In particular, the effects of radiothermolysis, degassing and carbonisation are under examination. Recent results on the high fluence and high ion current density implantation are reviewed. Post-implantation oxidation phenomenon of the radiationdamaged polymers is described in connection to the structural alteration. Depth distribution of various implanted species in polymers is one of the significant items under consideration. Main aspects of nucleation and growth of the metal nanoparticles (NPs) under the implantation conditions leading to the exceeding the metal solubility limit in the dielectric matrix are described as a special case of ion-beam treatment. The implantation-induced polymer modification is found to be originating a spectrum of new properties, i.e. significant changes in conductance, optical and magnetic characteristics, surface hardness, adhesion and other parameters that is reviewed with relation to practical applications.
Electronic properties of ion-implanted polymer films
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 1997
Electronic properties of polystyrene-acrylonitrile (PSA) films, implanted with 20-175-keV nitrogen to a dose range of 5 X 1013-5 X 1016 ions/cm', were studied. Electrical conductivity of the films increases more than 17 orders of magnitude with increasing ion dose and beam energy. Temperature dependence of the conductivity suggests a composite hopping conduction in the films. Temperature dependence of piezoresistance shows that the variable-range hopping conduction is also responsible for piezoresistivity in the films. Hall coefficient measurements show no hall voltage with the experimental limit of-1 p.V, indicating that a large number of carriers (> 10" cme3) are present in the implanted films. Optical absorption indicates a progressive optical gap closing as ion dose increases, suggesting a gradual phase transition from insulator to semiconductor. Graphitic properties were observed in the PSA film implanted with 175-keV N: ions to a dose of 5 X lOI ions/cm2.
Track structure in some heavy-ion irradiated plastic films
International Journal of Radiation Applications and Instrumentation. Part D. Nuclear Tracks and Radiation Measurements
The changes occurring in thin polyethylene terephthalate (PETP), polycarbonate (PC) and polypropylene (PP) films irradiated with heavy ions have been investigated. The track etching properties were studied in the submicroscopic diameter range of 1-60 rim. The method of absorption spectroscopy in ultraviolet (u.v.) and infrared (i.r.) regions, viscosimetry of polymer solution and sol-gel analysis were used to investigate radiation chemical processes in the polymers. It has been found that in all three polymers both the chain rupture and cross-linking processes occur simultaneously. The chain ruptures predominate in the track core with a diameter of several nanometers. The cross-linking process takes place in the vicinity of the track core at radii of up to 30-50 nm and appears most clearly in PETP where cross-linking events prevail over the destruction at large distances from the ion path.
Thermal regression of latent tracks in the polymer irradiated by high energy heavy ions
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2004
The influence of heat treatment (85-180°C) on latent tracks (LTs) in poly(ethylene terephthalate) (PET) films irradiated by Xe ions with energy of 1 MeV/nucleon was studied. The kinetics of the alkaline etching (layer-by-layer technique) was investigated. Thermal annealing rises the time of through-pore formation. The etching of through pores, investigated by Hagen-Poiseuille and atomic force microscopy (AFM) methods, was found to be nonlinear: steps were discovered at the etching diagram. They were associated with earlier detected zones of high chemical stability around the track (with the diameters of approximately 10 and 20 nm). Using the AFM method an appearance of surface craters after the irradiation was found. After the annealing the shape of these defects changed to the hillock form. From the analysis of the Raman and electron paramagnetic resonance (EPR) spectra it is supposed that the polymer structure in the LT area was changed towards carbonaceous phase with graphite-like inclusions, which are evolving under the annealing and affecting the sequential etching process.