This review article reports analyses of magnetron sputtering plasmas based on precise diagnostics by laser-induced fluorescence imaging spectroscopy. We show two-dimensional distribution of a radical density, anomalous ionization of metal atoms in high-pressure magnetron sputtering discharges, effects of oxidation reactions in a reactive sputtering process for depositing a YBaCuO superconducting film, and the thermalization process of Fe atoms ejected from the target.
Sputtering-based metal ion sources were reviewed in comparison with ion sources based on arc discharges. This metal ion source has advantages of few generation of metal droplets which disturbs material processing on treated surfaces, but a problem of a low extracted ion current. However, various techniques were reported to enhance the metal ion current. Furthermore, this paper also explained merits on usage of metal ions for materials processing compared with that of metallic neutrals, together with some applications on formation of thin films with metal ions for manufacturing of ULSI semiconductor devices and surface modification of polymer films.
Magnetoresistive films used for read-heads of hard disc drives, magnetic random access memory devices, and magnetic sensors are fabricated by magnetron sputtering method. Since giant magnetoresistive and tunnel magnetoresistive films are composed of multilayered films, in which the thickness of each layer is in the nanometer range, high accuracy in thickness control and thickness uniformity is required for the sputtering systems. Film properties are also influenced by the quality of the vacuum during the fabrication process. This article addresses such issues on the deposition of magnetoresistive films, and introduces mass-production sputtering technologies capable of fabricating high quality multilayers. Furthermore, fabrication methods of the tunnel barrier in tunnel magnetoresistive devices are also described.
A large majority of insertion device (ID) vacuum sectors on the European Synchrotron Radiation Facility (ESRF) electron storage ring for the production of intense synchrotron radiation are equipped with flat vacuum vessels made of extruded aluminum using a non-evaporable Getter (NEG) coating to reduce the vacuum pressure bump along the chamber during the operation of the accelerator. After the in-situ activation of the sputtered film by bake-out of the vacuum system the NEG pumps gases such as H2, CO and CO2 while CH4 and noble gases are not pumped. Because a low activation temperature for the NEG is necessary to be compatible with the mechanical limitations of the aluminum alloy, the NEG composition of TiZrV has been chosen. During operation of the ESRF electron storage ring a few hundreds of watts of synchrotron radiation fall on the walls of the ID chambers leading to photodesorption and photo-conditioning. The NEG coating is intended to provide distributed pumping and reduced photodesorption to keep the generation of unwanted Bremsstrahlung radiation following the installation of a new vessel low. The deposit of the NEG coating takes place at a dedicated facility in the ESRF.
When it was soaked, more were desorbed In this study, gas desorption behaviors of graphite anode samples after various surface treatments and electrolyte solvent adsorption properties were investigated. The total amount of desorbed gases for the natural graphite samples increased after soaking in propylene carbonate, and increased even further with Raman R value, suggesting that surface defects act as an effective adsorption site for the electrolyte. These findings indicate that surface treatment such as a coating might be an effective remedy to reduce the amount of desorption gases in natural graphite samples. It was also found that the total amount of gas desorption largely decreased with the coating with polymer resin and subsequent heat treatment at 423 K for 12 hours in a medium of air. It is likely that the dominant gas species present in the natural graphite after the electrolyte soaking are dependent on the binding energy and the molecular structure of the electrolyte solvent.
Lithium niobate (LN) etching has been demonstrated with an electron cyclotron resonance (ECR) plasma and low-frequency bias. The etching was studied by using Ar, BCl3 and SF6 gases. The etch rates of BCl3 and SF6 are about 3.8 and 4.6 times higher than that of Ar, respectively. The highest etch rate (220 nm/min) was obtained under the condition of SF6 plasma and 1 MHz bias. The etching method which can fabricate micro-trenches with high-aspect ratio and smooth surfaces has been achieved.