ICMCTF2005 Session B4: Ion Beam Technologies

Monday, May 2, 2005 10:30 AM in Room Sunset

Monday Morning

Time Period MoM Sessions | Abstract Timeline | Topic B Sessions | Time Periods | Topics | ICMCTF2005 Schedule

Start Invited? Item
10:30 AM B4-1 Modification of Ceramic Coatings by Swift Heavy Ions
W. Bolse (Universtaet Stuttgart, Germany)
The formation of nuclear tracks (cylindrical amorphous zones of some nm in diameter and some micrometer in length) in insulators by the impact of single swift heavy ions (some MeV/amu) has been recognized already decades ago. Based on the different etchability of the track region as compared to the unaffected surrounding this phenomenon was succesfully used for detection of fission products and a regular ion track technology has evolved to create various functional devices by etching and refilling of such nuclear tracks. In recent years, because of the increased availability of high energy ion beams for the material sciences and also because of a significant improvement of high resolution analysis techniques in the sub-micrometer range, many new effects have been observed and the interest has focused on the properties of the tracks itself (besides the etchability) and on the atomic relocations occuring in the track on a ps-time scale, as well as on the effects of high fluence irradiation (multiple track overlap). It was found that the extrem conditions and the high atomic mobility in the track may initiate processes like interdiffusion at interfaces, collective transport of matter along the track axis, ultrafast phase formation far away from thermodynamic equilibrium, and may finally result in new and complex structures on a nm-scale. High fluence irradiations result in a global modification of the material, which only in a few cases can be understood as a simple direct sum of the single ion effects (like amorphisation, volume swelling), but often is a result of self-assembling processes driven by ion irradiation. In the present paper a brief overview over these new observations shall be given and the development from a single ion track to a self-organised surface structure will be discussed for selected examples.
11:10 AM B4-3 Plasma and Ion Beam Characterization by Non-Conventional Methods
H. Kersten, R. Wiese (INP Greifswald, Germany); H. Neumann (IOM Leipzig, Germany)
An essential requirement for the application of broad beam ion sources for surface processing is the knowledge of plasma and beam physical parameters and their interaction with macroscopic control functions. Common methods for plasma and ion beam characterization do not allow measurements of all related physical parameters, for example, it is very complicated to measure the contribution of fast neutrals in the ion beam, the plasma sheath in front of the screen grid or the ion momentum transfer itself. In order to overcome these problems, we use non-conventional methods for plasma and beam characterization.papargraph Firstly, the radial distribution of the energy influx of an Ar ion beam generated by an ECR -ion beam source towards a substrate surface has been determined at different distances from the grid system. For the measurement of the energy influx a special thermal probe has been used. The axial and radial distribution of the deposited power has been studied in dependence on typical process parameters of the ion source as supplied microwave-power, beam voltage, accelerator voltage, and gas flow, respectively. A comparison with Faraday cup measurements allows the selection of fast neutrals from the ion beam. Secondly, the ion beam profile has been visualized by the interaction of the ions with a micro-disperse particle cloud which has been charged and confined in an additional rf-plasma. By this method, the interaction of the ions (momentum transfer, ion drag) as well as inhomogeneities in the beam can be really observed and estimated. Thirdly, analytical photometry by means of a CCD-camera and different wave length filters as well as optical emission spectroscopy has been demonstrated near the screen grid. The influence of the gas flow and the grid voltages on the thickness of the small sheath was demonstrated.
11:30 AM B4-4 Study of Ion-Enhanced Etching of High-k Dielectric Films with Mass-Analyzed Ion Beam
K. Karahashi (AIST, Japan)

Dry etching with reactive plasma has been widely used in the fabrication of semiconductor devices. In the view of the development of integrated semiconductor devices, more precise control of the etching process is required for further progress. It has been known that reactive ion species and reactive neutral species, which are produced in plasma, play a great role in etching reactions. However, the mechanism for the etching reaction has not yet been quantitatively described. It is necessary to clarify the roles of individual reactive ion bombardments and neutral species. A beam experimental method is very useful tool for investigation of interaction of individual species with surfaces. We have developed a mass analyzed low-energy ion beam and molecular beam system to investigate an interaction of reactive ion and neutral species with surfaces. As advanced high-k gate dielectrics, such as HfO2, are being developed to replace SiO2 in the near future generation of microelectronics devices, understanding their plasma etch characteristics becomes vital for introducing the new materials into the manufacturing process. We studies on the interactions of HfO2 with Cl+, BClx+ (X = 1, 2) and SiCl x+ (X = 1, 2, 3), using the mass-analyzed ion beam apparatus. Etching yields increase with increasing number of chlorine atoms contained in the incident ions, and etching products are hafnium chlorides. The kinetic energy of etching products was larger than 0.1 eV. Therefore, products are different from thermally desorbed molecules. This indicates that desorption is caused by the momentum transfer to hafnium chloride.

This work was supported by NEDO.

12:10 PM B4-6 Self-Assembled Nano-Tile of Zinc-Blende SiC on Si(100) using Organometallic Ion Beam Deposition with Simultaneous Electron Beam Irradiation
T. Matsumoto, M. Kiuchi (National Institute of Advanced Industrial Science and Technology (AIST), Japan); S. Sugimoto, S. Goto (Osaka University, Japan)
The self-assembled silicon carbide (SiC) nano-dots were fabricated by the organometallic ion beam deposition with the simultaneous electron beam irradiation. The precursor of methylsilicenium ion (SiCH3+) was generated from dimethylsilane (SiH2(CH3)2) in a Freeman type ion source. The SiCH3+ ions were accelerated to 25 keV and mass-selected by a sector magnet. In the front of the substrate, the SiCH3+ ions were decelerated to 100 eV and deposited on Si(100) substrate at the growth temperature of 600 ° C. During the SiC formation, the electron beam was simultaneously irradiated to the substrate surface with the incident angle of 2-3 degrees. The pressure of the deposition chamber was kept below 1.0x10-8 Torr. The characteristics of the SiC nano-dots were analyzed by reflection high-energy electron diffraction (RHEED) and atomic force microscope (AFM). The crystal structure of the SiC nano-dots was zinc-blende SiC (3C-SiC) and the SiC nano-dots were heteroepitaxy. The AFM observation revealed that the SiC nano-dots formed in the shape of nano-tiles. The edge length of the self-assembled SiC nano-dots was 40 nm and the height of them was 10 nm.
Time Period MoM Sessions | Abstract Timeline | Topic B Sessions | Time Periods | Topics | ICMCTF2005 Schedule