In S. Choi

Study on the electrical properties of ITO films deposited by facing target sputter deposition

This study examined the mechanism for the change in the electrical properties (carrier concentration (n) and mobility (µ)) of tin-doped indium oxide (ITO) films deposited by magnetron sputtering in a confined facing magnetic field. The relationship between the carrier concentration and the mobility was significantly different from the results reported for ITO films deposited by other magnetron sputtering processes. The lowest resistivity obtained for ITO films deposited in a confined facing magnetic field at low substrate temperatures (approximately 120 ◦ C) was 4.26 × 10 −4 � cm at a power density of 3Wcm −2 . Crystalline ITO films were obtained at a low power density range from 3 to 5Wcm −2 due to the increase in the substrate temperature from 120 to 162 ◦ C. This contributed to the increased carrier concentration and decreased electrical resistivity. X-ray photoelectron spectroscopy revealed an increase in the concentration of the Sn 4+ states. This was attributed to the formation of a crystalline ITO film, which effectively enhanced the carrier concentration and reduced the carrier mobility.

The shear impact wear behavior of Ti compound coatings

Abstract The failure behavior of Ti compound coatings was evaluated under normal and shear impact conditions at room and elevated temperatures. Monolayers and combined multilayers of TiAlN and TiAlCN were deposited onto high speed steel by a cathodic arc ion plating process. The shear impact loading mode was obtained by rotating the coated disk specimen at a speed of 0.8 m s −1 under repetitive normal impact loading of 10 N using a CoWC ball indentor with a frequency of 5 Hz. The impact resistance under normal impact loading appeared to be higher in the order TiAlN, TiAlN/TiAlCN and TiAlCN in accordance with the adhesive strength measured by HRC indentation tests. Meanwhile the addition of shear force during repetitive normal impact loading by specimen rotation reduced significantly the failure resistance of all the films, both at room temperature and 600°C, with a change in failure mode. It was observed through progressive failure analysis with increasing repetitive loading cycles that the failure under shear impact loading was accelerated owing to the promotion of crack formation as well as laminated fragmentation by increasing tensile and shear stresses at the ball trailing zone resulting from tracking forces during repetitive instantaneous impacting and sliding. The propensity for failure became more severe owing to substrate softening for all the coatings as the temperature increased to 600°C.

Development and characterization of TiN coatings by ion beam assisted deposition process for improved wear resistance

TiN thin layers have been deposited on mould and die steel STD11 by ion beam assisted deposition (IBAD) process and the wear behaviour of the TiN-coated steel has been evaluated. The synthesis of the TiN film has been performed by irradiation of nitrogen or Xe ions under various nitrogen partial pressures with in situ Ti evaporation at an accelerating voltage range from 25 to 40 keV below 200 °C. TiN coating by Xe irradiation was more effective in enhancing the surface hardness and wear resistance. The formation behaviour and mechanical properties of TiN films synthesized by the IBAD process are discussed with Auger electron spectroscopy, X-ray diffraction and other analysis data. In addition, the performance of TiN coatings on precision moulds and dies in semiconductor manufacturing lines is also discussed.