Reactive sputtering of hard nitride coatings using asymmetric-bipolar pulsed DC generator

Hard coatings of TiN, CrN, TiAlN and Si3N4, which exhibit a large variation in their electrical resistivities, have been prepared in an unbalanced magnetron sputtering system using an asymmetric-bipolar pulsed DC generator. TiN, CrN and TiAlN coatings, which exhibit fairly low electrical resistivities as compared to Si3N4, have also been prepared using a DC generator in the same sputtering system under identical deposition conditions. The properties of these coatings are compared with the pulsed deposited coatings. X-ray diffraction, X-ray photoelectron spectroscopy, nanoindentation tester, atomic force microscopy and potentiodynamic polarization have been used to characterize the coatings. We present in detail the effect of pulsed sputtering onto the plasma properties (e.g., cathode voltage, cathode current and ion current) and onto the properties of the coatings (e.g., growth rate, surface roughness, hardness, porosity). Our studies show that a variety of hard nitride coatings (including dielectric) with superior properties and low defect density can be prepared using asymmetric-bipolar pulsed DC generator.

[1]  Klaus Goedicke,et al.  Pulsed magnetron sputter technology , 1993 .

[2]  H. Barshilia,et al.  Characterization of Cu/Ni multilayer coatings by nanoindentation and atomic force microscopy , 2002 .

[3]  W. Münz.  Titanium aluminum nitride films: A new alternative to TiN coatings , 1986 .

[4]  Jia-Hong Huang,et al.  Nanohardness of nanocrystalline TiN thin films , 2006 .

[5]  M. Griepentrog,et al.  Hard coatings on magnesium alloys by sputter deposition using a pulsed d.c. bias voltage , 1995 .

[6]  P. Kelly,et al.  Substrate effects during mid-frequency pulsed DC biasing , 2001 .

[7]  P. Kelly,et al.  Investigation into the properties of titanium based films deposited using pulsed magnetron sputtering , 2003 .

[8]  U. Heisig,et al.  Aspects and results of long-term stable deposition of Al2O3 with high rate pulsed reactive magnetron sputtering , 1993 .

[9]  O. Zywitzki,et al.  Nanocomposite oxide and nitride hard coatings produced by pulse magnetron sputtering , 2005 .

[10]  P. Kelly,et al.  A comparison of the properties of titanium-based films produced by pulsed and continuous DC magnetron sputtering , 2003 .

[11]  L. Toth.  Transition Metal Carbides and Nitrides , 1971 .

[12]  M. Griepentrog,et al.  Properties of TiN hard coatings prepared by unbalanced magnetron sputtering and cathodic arc deposition using a uni- and bipolar pulsed bias voltage , 1995 .

[13]  H. Jehn.  Improvement of the corrosion resistance of PVD hard coating–substrate systems , 2000 .

[14]  D. W. Hoffman,et al.  Internal stresses in sputtered chromium , 1977 .

[15]  I. Safi,et al.  Recent aspects concerning DC reactive magnetron sputtering of thin films: a review , 2000 .

[16]  L. Hultman,et al.  Low‐energy ion irradiation during film growth for reducing defect densities in epitaxial TiN(100) films deposited by reactive‐magnetron sputtering , 1987 .

[17]  J. Schneider,et al.  Very-high-rate reactive sputtering of alumina hard coatings , 1997 .

[18]  D. Lamas,et al.  Residual stresses in titanium nitride thin films deposited by direct current and pulsed direct current unbalanced magnetron sputtering , 2006 .

[19]  Weidong Zhu,et al.  Characterization of pulsed dc magnetron sputtering plasmas , 2005 .

[20]  Lennart Karlsson,et al.  Ion induced stress generation in arc‐evaporated TiN films , 1995 .

[21]  M. Seah,et al.  Practical Surface Analysis , 1992 .

[22]  M. Åstrand,et al.  PVD-Al2O3-coated cemented carbide cutting tools , 2004 .

[23]  S. Inoue,et al.  Electrochemical evaluation of pinhole defects in TiN films prepared by r.f. reactive sputtering , 1997 .

[24]  W. Sproul.  New Routes in the Preparation of Mechanically Hard Films , 1996, Science.

[25]  J. Walkowicz,et al.  Pulsed-plasma assisted magnetron methods of depositing TiN coatings , 2000 .

[26]  J. Sellers.  Asymmetric bipolar pulsed DC: the enabling technology for reactive PVD , 1998 .

[27]  W. Sproul.  High-rate reactive DC magnetron sputtering of oxide and nitride superlattice coatings , 1998 .

[28]  I. Petrov,et al.  Microstructure modification of TiN by ion bombardment during reactive sputter deposition , 1989 .

[29]  M. Jagner,et al.  The residual stress in TiN films deposited onto cemented carbide by high-rate reactive sputtering , 1989 .

[30]  P. Kelly,et al.  Time-resolved investigation of plasma parameters during deposition of Ti and TiO2 thin films , 2003 .

[31]  Nathan I. Croitoru,et al.  Reactive-sputter-deposited TiN films on glass substrates , 1991 .

[32]  Y. Mai,et al.  Composition, residual stress, and structural properties of thin tungsten nitride films deposited by reactive magnetron sputtering , 2000 .

[33]  S. Goldsmith,et al.  Macroparticle contamination in cathodic arc coatings: generation, transport and control☆ , 1992 .

[34]  J. Vossen,et al.  Thin Film Processes , 1979 .

[35]  P. Yashar,et al.  High-rate reactive d.c. magnetron sputtering of ZrOx coatings , 1996 .

[36]  R. W. Hoffman,et al.  Stresses in thin films: The relevance of grain boundaries and impurities , 1976 .