Phase tailoring of tantalum thin films deposited in deep oscillation magnetron sputtering mode

Abstract

The effect of energetic ion bombardment on the properties of tantalum thin films was investigated. To achieve such energetic ion bombardment during the process the Ta thin films were deposited by deep oscillation magnetron sputtering (DOMS), an ionized physical vapor deposition technique related to high power impulse magnetron sputtering.The peak power was between 49 and 130 kW and the substrate was silicon at room temperature and ground potential. The directionality and the energy of the depositing species was controlled by changing the ionization fraction of the Ta species arriving at the substrate at different peak powers. In this work, the surface morphology (AFM), microstructure (SEM), structure (XRD) and hardness and Young's modulus (nanoindentation) of the films were characterized. The ion energy distributions (IEDs) were measured using an electrostatic quadrupole ion energy and mass spectrometer (HIDEN EQP 300). The IEDs showed that the DOMS process applies a very energetic (up to 120 eV) ion bombardment on the growing tantalum films. Therefore, with such conditions it was possible to deposit pure α-Ta (of 2 µm of thickness) without the use of additional equipment, i.e., without substrate bias or substrate heating. Conditions are therefore significantly different than in previous works, offering a much simpler and cheaper solution to up-scale for industrial operation.

Electronic structure of β-Ta films from X-ray photoelectron spectroscopy and first-principles calculations

“…In particular, for thin films, there is an additional phase with a more complicated tetragonal crystal structure called b-Ta that was discovered in 1965 [2]. For sputtered films, b-Ta is the most frequently observed phase, but where growth of a-Ta films [3] as well as mixed a and b-phases are reported [4]. Process development has not yet advanced to the level allowing for deposition of phase pure a-Ta films under industrial conditions.…”

Tantalum coating prepared by APCVD and in-vivo biological evaluation

“…Using atmospheric pressure and the sensed temperature T of the outer wall, and calculating and of Equation (2) using the values of E and provided by references [13] and [15], Equation (3) was developed: Figure 2 compares the thickness of the Ta coating calculated from Equation (3) with the measured thickness. The Ta coating was divided into three parts along the flow direction.…”

“…Using atmospheric pressure and the sensed temperature T of the outer wall, and calculating and of Equation ( 2) using the values of E and provided by references [13] and [15], Equation (3) was developed: XRD analyses of the two parts indicated different preferred orientations and phase compositions (Figure 3). Part I, with two peaks that corresponded to the (200) and (310) planes of α-Ta, had a preferred orientation in the (200) direction.…”

“…Physical vapour deposition (PVD) [7,12,13] and chemical vapour deposition (CVD) [2,5,6,11] are the most common deposition techniques used to prepare Ta coatings. Although PVD methods can produce thin coatings on flat substrates, it is difficult to coat intricate features [12,13]. CVD processes can prepare Ta coatings both on regular [11] and irregular substrates (e.g.…”

Detailed pathway for a fast low-temperature synthesis of strongly thermochromic W-doped VO2films with a low transition temperature

“…The thermochromic W-doped VO 2 layers were deposited using a controlled deep oscillation magnetron sputtering (DOMS) of a single V-W target. The DOMS is a modified version of HiPIMS with packages (macropulses) of short high-power micropulses [25,26]. Our motivation to apply this high-power discharge with short voltage pulses was to further increase discharge stability during the deposition by minimizing the number of microarcs on the V-W target and to utilize a different energetics of the reactive deposition process (particularly at the higher deposition-averaged target power density used, resulting in a high deposition rate of the W-doped VO 2 layers) compared with that during a standard HiPIMS deposition with separated high-power pulses at a much lower duty cycle.…”