Multi‐instrument characterization of HiPIMS and DC magnetron sputtered tungsten and copper films

Abstract

Funding information Kurt J. Lesker CompanyIn this work, copper and tungsten were sputtered onto silicon wafers by direct current magnetron sputtering (DCMS) and high-power impulse magnetron sputtering (HiPIMS). The resulting films were characterized by energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), atomic force microscopy (AFM), spectroscopic ellipsometry (SE), and X-ray diffraction (XRD). By EDX and XPS, all the sputtered films showed only the expected metal peaks. By XPS, the surfaces sputtered by DCMS were richer in oxygen than those produced by HiPIMS. By AFM, the surfaces were quite smooth. The root mean square (RMS) roughness values are as follows: 0.83 nm (W, HiPIMS), 1.10 nm (W, DCMS), 0.85 nm (Cu, HiPIMS), and 1.78 nm (Cu, DCMS). By SEM, the HiPIMS films exhibited smaller grain sizes, which was confirmed by XRD. The crystallite sizes estimated by XRD are as follows: 4 nm (W, body-centered cubic, HiPIMS), 13 nm (W, body-centered cubic, DCMS), 7 nm (W, cubic, HiPIMS), 14 nm (W, cubic, DCMS), 25 nm (Cu, HiPIMS), and 35 nm (Cu, DCMS). By SE, the HiPIMS surfaces showed higher refractive indices, which suggested that they were denser and less oxidized than the DCMS surfaces. K E Y W O R D S atomic force microscopy (AFM), copper (Cu), direct current magnetron sputtering (DCMS), energy dispersive X-ray spectroscopy (EDX), high-power impulse magnetron sputtering (HiPIMS), scanning electron microscopy (SEM), spectroscopic ellipsometry (SE), tungsten (W), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS)

High power impulse magnetron sputtering of tungsten: a comparison of experimental and modelling results

“…Sputter-deposited tungsten thin films exhibit two phases, the equilibrium α−W (A2 bcc) and the metastable β−W (A15 cubic) phases. HiPIMS-deposited tungsten films are denser, exhibit smaller grains and better adhesion [13][14][15] in addition to higher hardness, higher Young's modulus values, and smoother surfaces [13,16,17]. This is well demonstrated by Shimizu et al [15] who reported stress-free, unstrained single phase α−W thin films, deposited by applying a synchronized substrate bias to selectively increase the energy of the metal population of the ion bombardment.…”

Wear and Corrosion Resistance of CrN Films on Oxynitriding-treated Vanadis 8 Tool Steel <i>via</i> the DC Magnetron Sputtering Process

“…Magnets are often used in this type of sputtering to trap the electrons near the target surface and increase their effective path lengths, which substantially increases their ionization efficiencies. 19,20) Since RF (Radio Frequency) magnetron sputtering has its own difficulty for the requirement of impedance matching of the power supply, and also has low deposition rate. Whereby, this study explored the relatively easier technique of DC magnetron sputtering which does not have the impedance matching problem.…”

Modeling of high power impulse magnetron sputtering discharges with tungsten target

“…Deposition of tungsten thin films by dcMS and HiPIMS results in textured films that consists of two phases, the equilibrium α-W (A2 bcc) and the metastable β-W (A15 cubic). The HiPIMS-deposited films are denser, have smaller grains and better adhesion [13][14][15]. Furthermore, HiPIMS-deposited tungsten thin films exhibit enhanced properties, including smoother surfaces, higher hardness, and Young's modulus values [13,16,17].…”