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Title: Effects of Al content on grain growth of solid solution (Ti,Al)N films

Abstract

Substitutional solid solution (Ti{sub 1-x}Al{sub x})N films with different Al contents (0{<=}x{<=}0.41) were deposited onto unheated Si(100) substrates by reactive unbalanced close-field magnetron sputtering in an Ar-N{sub 2} gas mixture. The effect of Al atomic concentration on the sizes of crystal grains during deposition was investigated. X-ray diffraction analysis revealed that the incorporated Al atoms had an obvious impact on the grain growth of (Ti{sub 1-x}Al{sub x})N films and the average crystal grain size showed an exponential decay with Al atomic concentration. A phenomenological model was proposed to analyze this solute-drag effect occurring during film deposition. It was found that the presence of solute drag in normal grain growth resulted in a low kinetic growth exponent, and the exponential decay in average grain size with solute atomic concentration could be reproduced in our calculations.

Authors:
;  [1]
  1. Department of Manufacturing Engineering and Engineering Management, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China)
Publication Date:
OSTI Identifier:
20776944
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Vacuum Science and Technology. A, International Journal Devoted to Vacuum, Surfaces, and Films; Journal Volume: 24; Journal Issue: 1; Other Information: DOI: 10.1116/1.2148416; (c) 2006 American Vacuum Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ALUMINIUM COMPOUNDS; CRYSTALS; DEPOSITION; GRAIN GROWTH; GRAIN SIZE; MAGNETRONS; SOLID SOLUTIONS; SOLUTES; SPUTTERING; SUBSTRATES; THIN FILMS; TITANIUM COMPOUNDS; X-RAY DIFFRACTION

Citation Formats

Liu, Z.-J., and Shen, Y.G. Effects of Al content on grain growth of solid solution (Ti,Al)N films. United States: N. p., 2006. Web. doi:10.1116/1.2148416.
Liu, Z.-J., & Shen, Y.G. Effects of Al content on grain growth of solid solution (Ti,Al)N films. United States. doi:10.1116/1.2148416.
Liu, Z.-J., and Shen, Y.G. Sun . "Effects of Al content on grain growth of solid solution (Ti,Al)N films". United States. doi:10.1116/1.2148416.
@article{osti_20776944,
title = {Effects of Al content on grain growth of solid solution (Ti,Al)N films},
author = {Liu, Z.-J. and Shen, Y.G.},
abstractNote = {Substitutional solid solution (Ti{sub 1-x}Al{sub x})N films with different Al contents (0{<=}x{<=}0.41) were deposited onto unheated Si(100) substrates by reactive unbalanced close-field magnetron sputtering in an Ar-N{sub 2} gas mixture. The effect of Al atomic concentration on the sizes of crystal grains during deposition was investigated. X-ray diffraction analysis revealed that the incorporated Al atoms had an obvious impact on the grain growth of (Ti{sub 1-x}Al{sub x})N films and the average crystal grain size showed an exponential decay with Al atomic concentration. A phenomenological model was proposed to analyze this solute-drag effect occurring during film deposition. It was found that the presence of solute drag in normal grain growth resulted in a low kinetic growth exponent, and the exponential decay in average grain size with solute atomic concentration could be reproduced in our calculations.},
doi = {10.1116/1.2148416},
journal = {Journal of Vacuum Science and Technology. A, International Journal Devoted to Vacuum, Surfaces, and Films},
number = 1,
volume = 24,
place = {United States},
year = {Sun Jan 15 00:00:00 EST 2006},
month = {Sun Jan 15 00:00:00 EST 2006}
}
  • Gradient (Ti,Al)N films were prepared on high speed steel (HSS) and Si (111) wafers by using two Ar{sup +} beams to sputter a titanium target and an aluminum target separately, and a third N{sup +} beam to simultaneously bombard the growing film to assist deposition. The effects of the Ti/Al atomic ratio in the films on properties such as hardness, stress, and adhesion strength were investigated systematically. The results indicated that both the hardness and the adhesion of gradient (Ti,Al)N films to steel substrates exhibited {open_quotes}peak{close_quotes} type changes with an increase of the Ti/Al atomic ratio, and a maximum hardnessmore » of 3780thinspkgfthinspmm{sup {minus}2} was reached at a Ti/Al ratio of 5.35. The compressive stress of gradient (Ti,Al)N films increased with increasing Al content in the films. It was found that extreme hardness, high adhesion strength and low stress gradient (Ti,Al)N films can be synthesized on low temperature HSS steel by using the ion beam assisted deposition process.« less
  • Oriented thin films of perovskite-related Sr {sub n} {sub +1}Ti {sub n} O{sub 3} {sub n} {sub +1} Ruddlesden-Popper phases (n=1, 2, 3) were grown on (001) single-crystalline SrTiO{sub 3} substrates. Preparation of the films was carried out by wet chemical deposition from metalorganic Sr-Ti solutions (rich in Sr) and subsequent conversion into the crystalline state by thermal treatment in air atmosphere at a maximum temperature of 700 deg. C. Solutions were prepared by a modified Pechini method. The films were investigated by wide-angle X-ray scattering and high-resolution transmission electron microscopy. The phase content of powders prepared from the driedmore » solutions and annealed under similar conditions differed from that present in the films, i.e. only polycrystalline SrTiO{sub 3} was detected together with oxides of Ti and Sr. - Graphical abstract: Cross-sectional image of an oriented chemical solution deposited thin film obtained by high-resolution transmission electron microscopy. Periodical spacings corresponding to SrTiO{sub 3} substrate (right) and Sr{sub 2}TiO{sub 4} Ruddlesden-Popper phase (n=1) film region (left) are marked.« less
  • In situ x-ray diffraction has been used to characterize the growth and microstructure of wear protective Ti{sub 1-x}Al{sub x}N thin films. The films were deposited onto oxidized Si(100) wafers in a sputter chamber mounted onto a six-circle goniometer located at a synchrotron-radiation beam line. Off-plane and in-plane x-ray diffraction data were recorded in situ during growth, in order to follow the development of microstructure and preferred orientation as a function of film thickness. The measurements were supplemented by ex situ cross-sectional transmission electron microscopy analyses. The films were deposited by reactive cosputtering from metallic Ti and Al targets in Ar/N{submore » 2} gas mixtures at substrate temperatures of 150 and 300 deg. C, substrate bias voltages of -30 and +10 V, and deposition rates between 0.9 and 0.3 A/s. The film composition was changed between pure TiN and Ti{sub 0.91}Al{sub 0.09}N. Films deposited at higher deposition rates show columnar structure with competitive growth between (001) and (111) crystalline orientation, which slowly evolves into a (111) preferred orientation containing inter- and intracolumn porosities. Reducing the deposition rate to 0.3 A/s leads to an almost complete (001) preferred orientation with reduced surface roughness, practically independent of the deposition temperature. As the stress state of the films remains low for both deposition rates, it is suggested that the ion-to-neutral arrival rate (J{sub I}/J{sub Ti+Al}) determines the texture development rather than the stress. This is corroborated by applying a positive substrate bias, which, by suppressing ion impingement, leads back to an evolving (111) preferred orientation.« less
  • Several different types of thin films, TiB{sub 0.65}, TiB{sub 0.62}N{sub 0.18}, TiB{sub 0.61}N{sub 1.04}, and pure TiN, were deposited on Si(100) substrates at 500 deg. C by reactive unbalanced close-field dc-magnetron sputtering using two Ti and two TiB{sub 2} targets. The oxidation experiments of these films were carried out in air at fixed temperatures in a temperature regime of 600-1000 deg. C. As-deposited and oxidized films were characterized and analyzed using x-ray diffraction, plan-view and cross-sectional scanning electron microscopies, atomic force microscopy, and x-ray photoelectron spectroscopy (XPS). It was found that the microstructure and bonding configuration of Ti-B-N thin filmsmore » were strongly dependent on nitrogen flow rate during deposition. Depending upon the amount of N addition, the films showed two- or three-phase nanocomposite structure. Nitrogen-free films were amorphous compound comprising of Ti and TiB{sub 2} (Ti-TiB{sub 2} compound). At 10 at. % N addition (TiB{sub 0.62}N{sub 0.18}), the films consisted of mainly TiN and TiB{sub 2} bondings with microstructures comprising of nanocrystalline (nc)-Ti(N) embedded in an amorphous (a)-TiB{sub 2} matrix. As the N concentration increased up to 38 at. % (TiB{sub 0.61}N{sub 1.04}), the films consisted of nc-TiN in a-(TiB{sub 2}, BN) matrix. The oxidation experiment illustrated that the nanocomposite TiB{sub 0.61}N{sub 1.04} thin films exhibited a much higher high-temperature oxidation resistance than TiN, TiB{sub 0.65}, and TiB{sub 0.62}N{sub 0.18} thin films. A two-stage oxidation process took place in these nanocomposite films in the whole temperature regime. A low oxidation rate accompanied with formation of small-grained Ti oxide occurred below 800 deg. C, while above 800 deg. C a rapid oxidation process accompanied with formation of large-grained Ti oxide with rough surface took place. It is believed that the two-stage oxidation process was related to oxidation resistance of nanocrystallites and thermal stability of amorphous matrix phase. By XPS, the oxides were determined to consist mainly of various types of Ti oxides in the oxidation temperatures of 600-1000 deg. C, such as TiO, TiN{sub x}O{sub y}, Ti{sub 2}O{sub 3}, and TiO{sub 2}. It was also found that no elemental B was detected in oxide formed above 600 deg. C, which may be due to a low melting temperature of B{sub 2}O{sub 3}.« less
  • Reactive magnetron sputter epitaxy was used to deposit thin solid films of Sc{sub 1-x}Al{sub x}N (0<=x<=1) onto MgO(111) substrates with ScN(111) seed layers. Stoichiometric films were deposited from elemental Sc and Al targets at substrate temperatures of 600 deg. C. The films were analyzed by Rutherford backscattering spectroscopy, elastic recoil detection analysis, x-ray diffraction, and transmission electron microscopy. Results show that rocksalt structure (c)-Sc{sub 1-x}Al{sub x}N solid solutions with AlN molar fractions up to approx60% can be synthesized. For higher AlN contents, the system phase separates into c- and wurtzite structure (w)-Sc{sub 1-x}Al{sub x}N domains. The w-domains are present inmore » three different orientations relative to the seed layer, namely, Sc{sub 1-x}Al{sub x}N(0001)||ScN(111) with Sc{sub 1-x}Al{sub x}N[1210]||ScN[110], Sc{sub 1-x}Al{sub x}N(1011)||ScN(111) with Sc{sub 1-x}Al{sub x}N[1210]||ScN[110], and Sc{sub 1-x}Al{sub x}N(1011)||ScN(113). The results are compared to first-principles density functional theory calculations for the mixing enthalpies of c-, w-, and zinc blende Sc{sub 0.50}Al{sub 0.50}N solid solutions, yielding metastability with respect to phase separation for all temperatures below the melting points of AlN and ScN.« less