RBS Depth Profiling Analysis of (Ti, Al)N/MoN and CrN/MoN Multilayers
© The Author(s). 2017
Received: 27 November 2016
Accepted: 14 February 2017
Published: 1 March 2017
(Ti, Al)N/MoN and CrN/MoN multilayered films were synthesized on Si (100) surface by multi-cathodic arc ion plating system with various bilayer periods. The elemental composition and depth profiling of the films were investigated by Rutherford backscattering spectroscopy (RBS) using 2.42 and 1.52 MeV Li2+ ion beams and different incident angles (0°, 15°, 37°, and 53°). The microstructures of (Ti, Al)N/MoN multilayered films were evaluated by X-ray diffraction. The multilayer periods and thickness of the multilayered films were characterized by scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HR-TEM) and then compared with RBS results.
Multilayered, multicomponent, and nanostructured films are widely used in modern material engineering for their great contributions to improving protective properties of versatile industrial products involving hardness, wear, and corrosion resistance, oxidation resistance at high temperature [1–5]. Generally, a multilayered film containing two alternating sublayers has a significant parameter of modulation period defined as the thickness of a bilayer at nanoscale. Among the multilayer-film family, hard nitride-based coatings as one of the most prospective functional materials are so attractive that have been exploring by means of the optimized preparation processes and novel analytical techniques [6–9]. It has already been proved that the multilayered coatings have better properties compared with the monolayers [10–12] because the combination of two kinds of coatings can provide superior performance for the cutting tools and the thickness of the sublayer inlayed in the multilayered structure plays a significant role for vigorous properties of nano-composite coatings [13, 14]. It is necessary to adopt appropriate methods to fabricate and probe new multilayered structure films for further industrial application.
MoN films are remarkable for the self-lubrication over a wide temperature range, which leads to a low-coefficient friction and low wear rate [15–17]. The excellent tribological signatures are introduced by the formation of lubricious oxides, such as MoO3 demonstrated by Koshy . CrN coatings can exhibit the extraordinary oxidation, wear, and corrosion resistance [19, 20] while has rather high-friction coefficient (0.4–0.8 in air) [21–23]. Fabrication of CrN/Mo2N multilayered structure is an effective route to decrease the friction coefficient of bearing coatings like CrN from 0.6–0.8 to 0.3–0.4 at room temperature. TiAlN coatings are usually used as the cutting tools, wear protections, and contact materials in the microelectronics due to its high hardness, chemical inertness, and thermodynamic stability [24–28]. Addition of Mo to TiAlN forming TiAlN/MoN multilayers or nanocomposites can diminish the friction coefficient ranging from 0.8–0.9 to 0.3–0.4 at higher temperatures [29, 30]. The super hardness in nano-composite thin films is obtained when the small crystallites are detached by a discrepant boundary with the high cohesive strength (Patscheider et al.) . Briefly, it is extremely important and useful to analyze the multilayered structure consisting of MoN, CrN as well as other functional interlayers in ion plating applications.
Rutherford backscattering spectrometry (RBS) based on elastic collision has been utilized as a conventional tool for analysis of the thin film or the solid compound comprised intrinsic elements with enormous mass difference [32–34]. It is determinate to act as one of the most efficient non-destructive techniques for the depth profiling among nanoscale characterizations for the thin film, which can evaluate the relative atomic concentration as a function of depth at a unit of the areal density. It can also give the evidence on the atomic diffusion located at the interface of two individual layers as depth profiling in the film resulted from annealing. Usually, cross-section scanning electron microscopy (SEM) and transmission electron microscopy (TEM) are employed to probe the microstructure feature of the multilayered films. However, the destructiveness and complication of accurate sampling detected by these methods have to take into consideration. By contrast, RBS is certainly a better alternative for the composition and depth profiling due to its significant advantage and quantification for both the thin films and bulk materials [35, 36].
To some extent, the systemic resolution of RBS measurement depends on the incident ion species, initial energy, and energy resolution of detector besides vacuum degree for beam transportation. Frequently, selecting proton as incident ion has better sensitivity for light element detection than 4He2+ or other heavy ions ascribed to its great penetrability and smaller straggling, but it is not sensitive for ultrathin film as the multilayered films consisting of number of sublayers at a thickness of several nanometers. In order to obtain more reasonable detection results, a heavier incoming MeV ion is probable to contribute much better mass resolution and depth resolution instead of energy resolution.
In this paper, we have used 2.42 and 1.52 MeV 7Li2+ ion beams as projectile and different incident angles (0°, 15°, 37°, and 53°) to study the structure of (Ti, Al)N/MoN and CrN/MoN multilayered films. X-ray diffraction (XRD) was employed to probe the microstructure of (Ti, Al)N/MoN. The element composition of CrN/MoN multilayered films was measured by Sirion FEG SEM with EDAX genesis 7000 EDS. X-ray photoelectron spectra (XPS, XSAM800 KRATOS) collected by Thermo Scientific Escalab 250 Xi spectrometer were used to confirm the elemental composition of (Ti, Al)N/MoN. At the same time, SEM and cross-sectional high resolution TEM (HRTEM) were also used to measure their modulation periods comparing with the results of RBS.
The (Ti, Al)N/MoN multilayered films were deposited on the polished Si(100) with Ti0.7Al0.3 and Mo targets by the cathodic arc plasma deposition system whose configuration was detailed in our previous work . During the deposition process, the nitrogen gas was fed into the chamber and the deposition pressure kept at 2.5 Pa while bias voltage of the substrate was −300 V. The (Ti, Al)N/MoN films with different modulation periods were fabricated by varying the substrate rotation speed (SRS) from 1 to 3 rpm. Similarly, the CrN/MoN multilayered films were deposited on the Si (100) substrates using Cr and Mo metal targets with a purity of more than 99.95%. Prior to deposition, the substrates were cleaned by a standard technique using ultrasonic degreasing and exposed to bombardment of Cr+ ions at −800 V for 10 min so as to remove the surface contaminants and reduce the roughness. After feeding reactive nitrogen gas to deposition process continuously, the vacuum and negative bias were about 2.0 Pa and 200 V, respectively. To achieve the multilayered films with various modulation periods, SRS was also varied from 2 to 6 rpm.
Results and Discussion
This subtle phase angle shift may be ascribed to the reduction of lattice parameter which is probable to be explained by smaller interstitial Al3+ ions replacing Ti3+ ions. It is concluded that the bilayer in films has no influence on the phase formation at the different SRSs but can interact on grain sizes of crystals in the sublayers.
where, Z1, Z2 is atomic number of the incident ion and the target atom, M1, M2 is their relative atomic mass, and E and θ are corresponding to incident ion energy and backscattering angle, respectively . Decreasing the initial energy E 0, the backscattering cross section is increased that can dedicate better mass differences to target atoms in the sample. In Fig. 5c, when E 0 is reduced from 2.42 to 1.52 MeV, the backscattering yields of all the elements have increased to five times higher than that of 2.42 MeV. A straightforward variety is that visible signal peaks from neighbor-surface sublayers reduce, such as from 7 to 5 peaks for Mo, revealing a shallower detected depth in the same condition. Comparatively, the fitting data give a thickness of 1.9 × 1017 ~ 2.8 × 1017 atoms/cm2 for monolayer MoN and 1.15 × 1017 ~ 1.8 × 1017 atoms/cm2 for monolayer (Ti, Al)N, which is corresponding to an average thickness of 47.5 and 34.5 nm, respectively. When the angle of incidence changes from 0° to 53° (Fig. 5d), the effective thickness of the outmost monolayer film is increased intensely while the sublayers located in deeper positions have worse energy resolution, especially for larger tilt angle 37° and 53°. It is concluded that incident ion beam with low energy can lead to a relative shallower detected depth but can be beneficial to detect ultrathin film beneath 10 nm.
where, Y is yield of backscattered ions, σ R is Rutherford backscattering cross section, Q is total number of incident ion charges, ρ is bulk density of target sample, and d 0/cos α is the detected depth when the incident angel is α. The fitting data from SIMNRA give the areal density ρ ⋅ d 0/cos α at atoms/cm2 (unit) . The thickness (nm) is proportional to the areal density and molecular mass of compound. However, during quantitative RBS measurements via fitting data of CrN/MoN, the areal density and molecular mass of homogenous compound instead of hybridized structures consisting of single phase compound and amorphous phase mixtures were taken into inconsideration that can lead to calculated value is larger than the actual value.
We have analyzed (Ti, Al)N/MoN and CrN/MoN multilayered films on Si substrate by using 1.52 and 2.42 MeV Li2+ ion beams of RBS. The results demonstrated that the 1.52 MeV ion beam is superior in depth resolution, whereas the 2.42 MeV ion beam is advantageous for deeper path detection. It is seen that SIMNRA simulation data agree well with the SEM results of (Ti, Al)N/MoN films at 2 rpm. The scattering cross-section peaks were broadened gradually with increases in the angle of incidence (α) of ion beam which implies the improvement in the detected resolution at a certain depth. The monolayers of CrN and MoN are 8.5 and 10 nm, respectively, when the film has smallest bilayer period 18.5 nm which provided that a relative good depth resolution about 10 nm. Finally, RBS depth profiling proved to be a useful structural tool to evaluate the multilayer structure and chemical composition.
This work was supported by National Natural Science Foundation of China under grants 11375133 and 11405133, Suzhou Scientific Development Project ZXG201448, and Wuhan Science and Technology Bureau under 2016030409020219.
DF, CL, and BH conceived and designed the study. ZW, NL, and WZ performed the experiments. BH wrote the paper. ZW, ND, and KKK reviewed and edited the manuscript. All authors read and approved the manuscript.
The authors declare that they have no competing interests.
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- Subramanian C (1993) Strafford Review of multicomponent and multilayer coatings for tribological applications. Wear 165:85–95Google Scholar
- Shtansky DV, Kiryukhantsev-Korneev PV, Bashkova IA, Sheveiko AN, Levashov EA (2010) Multicomponent nanostructured films for various tribological applications. Int J Refract Met H 28:32–39Google Scholar
- Knotek O, Löffler F, Krämer G (1992) Multicomponent and multilayer physically vapour deposited coatings for cutting tools. Surf Coat Technol 54–55:241–248Google Scholar
- Hopple GB, Keem JE, Loewenthal SH (1993) Development of fracture resistant, multilayer films for precision ball bearings. Wear 162–164(1):919–924Google Scholar
- Musil J (2012) Hard nanocomposite coatings: thermal stability, oxidation resistance and toughness. Surf Coat Technol 207:50–65Google Scholar
- Nordin M, Larsson M, Hogmark S (1998) Mechanical and tribological properties of multilayered PVD TiN/CrN, TiN/MoN, TiN/NbN and TiN/TaN coatings on cemented carbide. Surf Coat Techno 106:234–241Google Scholar
- Wang X, Kwon PY, Schrock D, Kim DW (2013) Friction coefficient and sliding wear of AlTiN coating under various lubrication conditions. Wear 304:67–76Google Scholar
- Hsieh JH, Tan ALK, Zeng XT (2006) Oxidation and wear behaviors of Ti-based thin films. Surf Coat Technol 201:4094–4098Google Scholar
- Liu AH, Deng JX, Cui HB, Chen YY, Zhao J (2012) Friction and wear properties of TiN, TiAlN, AlTiN and CrAlN PVD nitride coatings. Int J Refract Met H 31:82–88Google Scholar
- Paldey S, Deevi SC (2003) Single layer and multilayer wear resistant coatings of (Ti,Al)N: a review. Mater Sci Eng A 342:58–79.Google Scholar
- Carvalho NJM, Zoestbergen E, Kooi BJ, Hosson JTMD (2003) Stress analysis and microstructure of PVD monolayer TiN and multilayer TiN/(Ti,Al)N coatings. Thin Solid Films 429:179–189Google Scholar
- Surzhenkov A, Adoberg E, Põdra P, Sergejev F, Mere A, Viljus M, Mikli V, Antonov M, Kulu P (2012) Impact and Sliding Wear Properties of Single Layer, Multilayer and Nanocomposite Physical Vapour Deposited (PVD) Coatings on the Plasma Nitrided Low-Alloy 42CrMo4 Steel. Key Eng Mater 527:223–228Google Scholar
- Voevodin AA, Schneider JM, Rebholz C, Matthews A (1996) Multilayer composite ceramicmetal-DLC coatings for sliding wear applications. Tribol Int 29:559–570Google Scholar
- Urgen M, Eryilmaz OL, Cakir AF, Kayali ES, Nilufer B, Isik Y (1997) First-principles investigation of the structural, mechanical and electronic properties of the NbO-structured 3d, 4d and 5d transition metal nitrides. Surf Coat Technol 94–95:501–506Google Scholar
- Seibert F, Dobeli M, Fopp-Spori DM, Glaentz K, Rudigier H, Schwarzer N, Widrig B, Ramm J (2013) Comparison of arc evaporated Mo-based coatings versus Cr 1 N 1 and ta–C coatings by reciprocating wear test. Wear 298–299:14–22Google Scholar
- Zhu X, Yue D, Shang C, Fan M, Hou B (2013) Phase composition and tribological performance of molybdenum nitride coatings synthesized by IBAD. Surf Coat Technol 228:S184-S189Google Scholar
- Gilewicz A, Warcholinski B, Murzynski D (2013) The properties of molybdenum nitride coatings obtained by cathodic arc evaporation. Surf Coat Technol 236:149–158Google Scholar
- Koshy RA, Graham ME, Marks LD (2007) Synthesis and characterization of CrN/Mo 2 N multilayers and phases of Molybdenum nitride. Surf Coat Technol 202:1123–1128Google Scholar
- Jianliang L, Ningyi Z, Sproul WD, Moore JJ (2012) A comparison of the oxidation behavior of CrN films deposited using continuous dc, pulsed dc and modulated pulsed power magnetron sputtering. Surf Coat Technol 206:3283–3290Google Scholar
- Shan L, Wang YX, Li JL, Jiang X, Chen JM (2015) Improving tribological performance of CrN coatings in seawater by structure design. Tribol Int 82:78–88Google Scholar
- Cheng YH, Browne T, Heckerman B (2011) Mechanical and tribological properties of CrN coatings deposited by large area filtered cathodic arc. Wear 271:775–782Google Scholar
- Mo JL, Zhu MH (2009) Comparison of tribological properties of CrN, TiCN and TiAlN coatings sliding against SiC balls in water. Appl Surf Sci 255:7627–7634Google Scholar
- Chang ZK, Wan XS, Pei ZL, Gong J, Sun C (2011) Microstructure and mechanical properties of CrN coating deposited by arc ion plating on Ti6Al4V substrate. Surf Coat Technol 205:4690–4696Google Scholar
- Yu D, Wang C, Cheng X, Zhang F (2008) Optimization of hybrid PVD process of TiAlN coatings by Taguchi method. Appl Surf Sci 255:1865–1869Google Scholar
- Beckers M, Schell N, Martins RMS, Mücklich A, Möller W (2006) Phase stability of epitaxially grown Ti2AlN thin films. Appl Phys Lett 89:074101Google Scholar
- Irudayaraj AA, Kuppusami P, Thirumurugesan R, Mohandas E, Kalainathan S, Raghunathan VS (2007) Influence of nitrogen flow rate on growth of TiAlN films prepared by DC magnetron sputtering. Surf Eng 23(1):7–11Google Scholar
- Beckers M, Schell N, Martins RMS, Mücklich A, Möller W (2005) The influence of the growth rate on the preferred orientation of magnetron-sputtered Ti–Al–N thin films studied by in situ x-ray diffraction. J Appl Phys 98:(4):479Google Scholar
- Chang YY, Wang DY (2007) Characterization of nanocrystalline AlTiN coatings synthesized by a cathodicarc deposition process. Surf Coat Technol 201:(15):6699–6701Google Scholar
- Madan A, Kim IW, Cheng SC, Yashar P, Dravid VP, Barnett SA (1997) Stabilization of Cubic AlN in Epitaxial AlN/TiN Superlattices. Phys Rev Lett 78:1743–1746Google Scholar
- Tavares CJ, Vidrago TC, Rebouta L, Riviere JP, Bourhis E, Denanot MF (2005) Optimization and thermal stability of TiAlN/Mo multilayers. Surf Coat Technol 200:288–292Google Scholar
- Patscheider J, Zehnder T, Diserens M (2001) Structure–performance relations innanocomposite coatings. Surf Coat Technol 146–147:201–208Google Scholar
- Hernandez-Velez M, Pirota KR, Paszti F, Navas D, Climent A, Vazquez M (2005) Magnetic nanowire arrays in anodic alumina membranes: Rutherford backscattering characterization. Appl Phys A 80:1701–1706Google Scholar
- Schubert J, Siegert M, Fardmanesh M, Zander W, Prömpers M, Buchal C, Lisoni J, Lei CH (2000) Superconducting and electro-optical thin films prepared by pulsed laser deposition technique. Appl Surf Sci 168:208–214Google Scholar
- Galindo RE, Gago R, Forniés E, Muñoz-Martín A, Font AC, Albella JM (2006) Nanometric resolution in glow discharge optical emission spectroscopy and Rutherford backscattering spectrometry depth profiling of metal (Cr, Al) nitride multilayers. Spectrochim Acta B 61:545–553Google Scholar
- Barradas NP, Jeynes C, Webb RP (1997) Simulated annealing analysis of Rutherford backscattering data. Appl Phys Lett 71:291–293Google Scholar
- Wang Y, Nastasi M (2009) Handbook of modern ion beam materials analysis, the second edition. Handbook of modern ion beam materials analysis, the second edition. Materials Research Society, WarrendaleGoogle Scholar
- Yousaf MI, Pelenovich VO, Yang B, Liu CS, Fu DJ (2015) Effect of bilayer period on structural and mechanical properties of nanocomposite TiAlN/MoN multilayer films synthesized by cathodic arc ionplating. Surf Coat Technol 282:94–102Google Scholar
- Mayer M (1999) SIMNRA, a simulation program for the analysis of NRA, RBS and ERDA. Am Inst Phys Conf Proc 475:541–544Google Scholar
- Sanjines R, Hones P, Levy F (1998) Sputter deposited chromium nitride based ternary compounds for hard coatings. Thin Solid Films 332:240–246Google Scholar
- Mo JL, Zhu MH (2009) Tribological oxidation behaviour of PVD hard coatings. Tribol Int 42:1758–1756Google Scholar
- Bertoti I (2002) Characterization of nitride coatings by XPS. Surf Coat Technol 151–152:194–203Google Scholar
- Rodriguez RJ, Garcia JA, Medrano A, Rico M, Sanchez R, Martinez R, Labrugere C, Lahaye M, Guette A (2002) Tribological behaviour of hard coatings deposited by arc-evaporation PVD. Vacuum 67:559–566Google Scholar
- Soto G, Cruz W, Farias MH (2004) XPS, AES, and EELS characterization of nitrogen-containing thin films. J Electron Spectrosc Relat Phenom 135(1):27–39Google Scholar
- Fix R, Gordon RG, Hoffman DM (1996) Low-temperature atmospheric-pressure metal-organic chemical vapor deposition of molybdenum nitride thin films. Thin Solid Films 288:116–119Google Scholar
- Kim GT, Park TK, Chung H, Kim YT, Kwon MH, Choi JG (1999) Growth and characterization of chloronitroaniline crystals for optical parametric oscillators : I. XPS study of Mo-based compounds. Appl Surf Sci 152:35–43Google Scholar
- Moulder JF, Stikle WF, Sobol PE, Bomben KD (1992) Handbook of X-ray photoelectron spectroscopy. Perkin-Elmer Corp, Eden PrairieGoogle Scholar
- Chu WK, Mayer JW, Nicolet MA (1978) Backscattering spectrometry. Academic Press, New York San Francisco LondonGoogle Scholar
- Tavares CJ, Rebouta L, Rivière JP, Girardeau T, Goudeau P, Alves E, Barradas NP (2004) Atomic environment and interfacial structural order of TiAlN/Mo multilayers. Surf Coat Technol 187:393–398Google Scholar
- Roessler W, Primetzhofer D, Bauer P (2013) Analysis of Mo/Si multilayers by means of RBS. Nucl Instrum Meth B 317:126–129Google Scholar