Deposition of MAX phase containing thin films from a (Ti,Zr)2AlC compound target
Clio Azina, Bensu Tunca, Andrejs Petruhins, Binbin Xin, Melike Yildizhan, Per O. Å. Persson, Jozef Vleugels, Konstantina Lambrinou, Johanna Rosén, Per Eklund
This work reports on sputter depositions carried out from a compound (Ti,Zr)2AlC target, whereupon Al-containing (Ti,Zr)C thin films (30-40 nm in thickness) were deposited on MgO(111) and Al2O3(0001) substrates at temperatures ranging between 500 and 900 °C. The presence of Al within the carbide structure was evidenced by lattice parameter variations. Furthermore, chemical analyses showed that the Al distribution throughout the film thickness was fairly homogeneous. Thicker films (80-90 nm) deposited from the same compound target consisted of the pseudo-binary (Ti,Zr)C and intermetallic compounds in the Ti-Zr-Al system up to 800 °C, as well as solid solution MAX phases with different Ti:Zr ratios at 900 °C. X-ray diffraction and transmission electron microscopy showed that both (Ti,Zr)2AlC and (Ti,Zr)3AlC2 solid solution MAX phases were formed. Moreover, this work discusses the growth mechanism of the thicker films, which started with the formation of the mixed (Ti,Zr)C carbide, followed by the nucleation and growth of aluminides, eventually leading to the formation of the MAX phases, which was the primary objective of the sputter depositions.
Herein we report on the reactivity between palladium, Pd, and the MAX phases, Ti${_2}$AlC, Ti${_3}$AlC${_2}$, Ti${_3}$SiC${_2}$ and Cr${_2}$AlC. Diffusion couples of Pd/MAX were heated to 900 °C under uniaxial stress of ~20 MPa for 2, 4, and 10 h in a vacuum (<1 Pa) hot press. The diffusion couples were examined using X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray spectroscopy. After heating to 900 °C for 10 h, the diffusion layer thicknesses in the Ti${_2}$AlC/Pd, Cr${_2}$AlC/Pd, Ti${_3}$AlC${_2}$/Pd and Ti${_3}$SiC${_2}$/Pd couples were found to be 35, 45, 105 an…
This work investigates the compatibility of $Zr_{2}AlC$ MAX phase-based ceramics with liquid LBE, and proposes a mechanism to explain the observed local $Zr_{2}AlC$/LBE interaction. The ceramics were exposed to oxygen-poor ($C_{O}\le2.2 \cdot10^{-10}$ mass%), static liquid LBE at 500°C for 1000 h. A new $Zr_{2}(Al,Bi,Pb)C$ MAX phase solid solution formed in-situ in the LBE-affected $Zr_{2}AlC$ grains. Out-of-plane ordering was favorable in the new solid solution, whereby $\textit{A}$-layers with high and low-Bi/Pb contents alternated in the crystal structure, in agreement with first-principles…
MAX phases have great potential under demands of both high-temperature and high-stress performance, with their mixed atomic bonding producing the temperature and oxidation resistance of ceramics with the mechanical resilience of metals. Here, we measure the mechanical properties up to 980C by nanoindentation on highly dense and pure Cr$_2$AlC, as well as after oxidation with a burner rig at 1200C for more than 29 hours. Only modest reductions in both hardness and modulus up to 980C were observed, implying no change in deformation mechanism. Furthermore, micro-cantilever fracture tests were car…
Recently, a group of MAX phases, (Mo$_{2/3}$Y$_{1/3}$)$_2$AlC, (Mo$_{2/3}$Sc$_{1/3}$)$_2$AlC, (W$_{2/3}$Sc$_{1/3}$)$_2$AlC, (W$_{2/3}$Y$_{1/3}$)$_2$AlC, and (V$_{2/3}$Zr$_{1/3}$)$_2$AlC, with in-plane ordered double transition metals, named iMAX phases, have been synthesized. Experimentally, some of these MAX phases can be chemically exfoliated into two-dimensional (2D) single- or multilayered transition metal carbides, so-called MXenes. Accordingly, the 2D nanostructures derived from iMAX phases are named iMXenes. Here, we investigate the structural stabilities and electronic structures of th…
The elastic properties and lattice dynamics of Ti$_2$AlC, Ti$_2$AlN, Ti$_2$GaC, Ti$_2$GaN, Ti$_2$PbC, Ti$_2$CdC and Ti$_2$SnC have been investigated using the density functional theory within the generalized gradient approximations as expressed in Quantum Espresso and VASP codes. The obtained lattice parameters are in agreement with the previous theoretical research and available experimental data. The elastic properties of the MAX phases under study have been calculated. The values of elastic anisotropy, Young's modulus, Poisson ratio and shear modulus reveal that the compounds are stable and…
Biaxially textured MgO templates have been successfully fabricated on several amorphous polymer films including Kapton tapes, polyimide, Poly(methyl methacrylate) (PMMA), and photoresist films using ion-beam-assisted-deposition (IBAD). With a Y2O3 buffer layer on polymer surfaces, roughening of the polymer surfaces due to preferential ion beam sputtering can be effectively reduced to meet the surface compatibility requirement for IBAD-MgO texturing. In-plane full-width-at-half-maximum (FWHM) of ~10.7 degrees and out-of-plane FWHM ~ 3.5 degrees have been obtained on homoepitaxial MgO films grow…
Using kinetic Monte Carlo simulations, we develop a framework to relate morphological properties and microscopic dynamics during island growth, coalescence, and initial formation of continuous heteroepitaxial films. The average island width is controlled by adatom mobility on the substrate. Subsequent evolution strongly depends on the Ehrlich-Schwöebel energy barrier $E_{ES}$ of the deposited material. As $E_{ES}$ decreases, islands becomes taller and their coalescence is delayed. For small islands and large $E_{ES}$, the global roughness increases as $W\sim{\text{thickness}}^{1/2}$ and the lo…
5$μ$m thick SmCo films were deposited onto Si substrates using triode sputtering. A study of the influence of deposition temperature (Tdep <= 600 degrees C) on the structural, magnetic and mechanical properties has shown that optimum properties (highest degree of in-plane texture, maximum in-plane coercivity and remanence (1.3 and 0.8 T, respectively), no film peel-off) are achieved for films deposited at the relatively low temperature of 350 degrees C. This temperature is compatible with film integration into Micro-Electro-Mechanical-Systems (MEMS). The deposition rate was increased from 3.6 …
Achieving high temperature ferromagnetism by doping transition metals thin films is seen as a viable approach to integrate spin-based elements in innovative spintronic devices. In this work we investigated the effect of Fe doping on structural properties of ZrO2 grown by atomic layer deposition (ALD) using Zr(TMHD)4 for Zr and Fe(TMHD)3 for Fe precursors and ozone as oxygen source. The temperature during the growth process was fixed at 350°C. The ALD process was tuned to obtain Fe doped ZrO2 films with uniform chemical composition, as seen by time of flight secondary ion mass spectrometry. The…
Detailed KMC-MD (kinetic Monte Carlo-molecular dynamics) simulations of hyperthermal energy (10-100 eV) copper homoepitaxy have revealed a re-entrant layer-by-layer growth mode at low temperatures (50K) and reasonable fluxes (1 ML/s). This growth mode is the result of atoms with hyperthermal kinetic energies becoming inserted into islands when the impact site is near a step edge. The yield for atomic insertion as calculated with molecular dynamics near (111) step edges reaches a maxima near 18 eV. KMC-MD simulations of growing films and a minima in the RMS roughness as a function of energy nea…
LaAlO3-Ba0.5Sr0.5TiO3 (LAO-BST) thin films, with different LAO contents, were deposited on Pt/Ti/SiO2/Si and (100) LaAlO3 substrate, via a pulsed laser deposition (PLD). Phase composition and microstructure of the LAO-BST thin films were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The LAO-BST thin films were solid solution of LAO nd BST, with lattice constant decreasing with increasing LAO content. The composition of (LAO)x(BST)1-x, estimated from the lattice constant of the thin films derived from the targets of 1/6, 2/6 and 3/6 LAO, was 0.143, 0.278, 0.47…
Recently, Bi2O2Se is discovered as a promising two-dimensional (2D) semiconductor for next generation electronics, due to its moderate bandgap size, high electron mobility and pronounced ambient stability. Meanwhile, it has been predicted that high quality Bi2O2Se-related heterostructures may possess exotic physical phenomena, such as piezoelectricity and topological superconductivity. Herein, we report the first successful heteroepitaxial growth of Bi2O2Se films on SrTiO3 substrates via pulsed laser deposition (PLD) method. Films obtained under optimal conditions show an epitaxial growth with…
5$μ$m thick NdFeB films have been sputtered onto 100 mm Si substrates using high rate sputtering (18 $μ$m/h). Films were deposited at ≤ 500 C and then annealed at 750 C for 10 minutes. While films deposited at temperatures up to 450 C have equiaxed grains, the size of which decreases with increasing deposition temperature, the films deposited at 500 C have columnar grains. The out-of-plane remanent magnetization increases with deposition temperature, reaching a maximum value of 1.4 T, while the coercivity remains constant at about 1.6 T. The maximum energy product achieved (400 kJ/m3) is…
When the coverage of the second atomic layer of Fe in an Fe/W(110) ultrathin film reaches a critical value, the system moves suddenly from a frustrated magnetic state without long-range order to an in-plane ferromagnetic state with long-range order, and displays many features of a percolation transition. Measurements of the magnetic susceptibility as the films are grown at 255 K show power law scaling that is limited by noise at low deposition, and by the dynamics of the paramagnetic, frustrated state at high deposition. Because the measurements represent a system driven by a finite field osci…
$β-Ga_2O_3$ has drawn significant attention for power electronics and deep ultraviolet (UV) photodetectors owing to its wide bandgap of ~ 4.4 - 4.9 eV and high electric breakdown strength ~7-8 MV/cm. Growth of $β-Ga_2O_3$ epitaxial thin films with high growth rate has been recently reported using low pressure chemical vapor deposition (LPCVD) technique. In this work, we have investigated the effect of growth temperature on $β-Ga_2O_3$ films grown on c-plane sapphire substrates using LPCVD. We performed growths by varying temperatures from 800$^°$C to 950$^°$C while keeping all other growth par…
The objective of this work was to study the RF sputtering process parameters optimisation for deposition of Silicon Nitride thin films. The process parameters chosen to be varied were deposition power, deposition duration, flow rate of argon and flow rate of nitrogen. The parameters were varied at three levels according to Taguchi L9 orthogonal array. Surface topology, film composition, coating thickness, coating resistivity and refractive index were determined using SEM, XRD, profilometer, Semiconductor device analyser and UV spectrometer respectively. The measured film thickness values range…
We introduce a simple method of an MgB2 film preparation using sequential electron-beam evaporation of B-Mg two-layer (followed by in-situ annealing) on the NbN buffered Si(100) substrate. The Transmission Electron Microscopy analyses confirm a growth of homogeneous nanogranular MgB2 films without the presence of crystalline MgO. A sensitive measurement of temperature dependence of microwave losses shows a presence of intergranular weak links close the superconducting transition only. The MgB2 films obtained, about 200 nm thick, exhibit a maximum zero resistance critical temperature of 36 K an…
We investigate sputtering of a Ti3SiC2 compound target at temperatures ranging from RT (no applied external heating) to 970 oC as well as the influence of the sputtering power at 850 oC for the deposition of Ti3SiC2 films on Al2O3(0001) substrates. Elemental composition obtained from time-of-flight energy elastic recoil detection analysis shows an excess of carbon in all films, which is explained by differences in angular distribution between C, Si and Ti, where C scatters the least during sputtering. The oxygen content is 2.6 at.% in the film deposited at RT and decreases with increasing depo…
This paper reports on the deposition of amorphous and crystalline thin films of Ga2O3 by reactive pulsed direct current magnetron sputtering from a liquid gallium target onto fused (f-) quartz and c plane (c-) sapphire substrates, where the temperature of the substrate is varied from room temperature (RT) to 800°C. The deposition rate (up to 37 nm/min at RT on f-quartz and 5 nm/min at 800°C on c-sapphire) is two to five times higher than the data given in the literature for radio frequency sputtering. Deposited onto unheated substrates, the films are X-ray amorphous. Well-defined X-ray diffrac…
Substrate temperature dependent dielectric and ferroelectric properties of (100) oriented lead-free Na$_{0.4}$K$_{0.1}$Bi$_{0.5}$TiO$_3$ thin films grown by pulsed laser deposition
We investigate the effect of post-deposition annealing (for temperatures from 848 K to 1273 K) on the chemical properties of crystalline Ta$_2$O$_5$ films grown on Si(100) substrates by radio frequency magnetron sputtering. The atomic arrangement, as determined by X-ray diffraction, is predominately hexagonal ($δ$-Ta$_2$O$_5$) for the films exposed to heat treatments at 948 K and 1048 K; orthorhombic ($β$-Ta$_2$O$_5$) for samples annealed at 1148 K and 1273 K; and amorphous for samples annealed at temperatures below 948 K. X-ray photoelectron spectroscopy for Ta $4f$ and O $1s$ core-levels wer…
Achieving superconductivity in infinite-layer nickelate thin films by aluminum sputtering deposition
Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay（阿尔伯特·费尔特实验室，法国国家科学研究中心，泰雷兹集团，巴黎萨克雷大学）；Laboratoire de Physique des Solides, CNRS, Université Paris-Saclay（固体物理实验室，法国国家科学研究中心，巴黎萨克雷大学）；Synchrotron SOLEIL（索莱尔同步辐射中心）
Demonstration of Si-doped Al-rich thin regrown Al(Ga)N films on AlN on sapphire templates with $\gt10^{15}/cm^3$ free carrier concentration using close-coupled showerhead MOCVD reactor
