Coatings for Core–Shell Composite Micro‐Lattice Structures: Varying Sputtering Parameters

Abstract

Magnetron sputtering has garnered increased attention as a versatile deposition method for generating novel core–shell composite nano‐ and micro‐lattice materials spanning a wide range of properties and functionalities. Sputtering offers an expansive material workspace consisting of a wide range of ceramics, single‐element metals, and alloy systems. However, achieving uniform coatings on such fine‐featured structures remains a challenge. Thus, herein, a foundational assessment of various sputtering configurations, cathode geometries, and deposition parameters is carried out to investigate their implications on the coating thickness and uniformity of 3D micro‐lattice scaffolds. Specifically, tetrahedral‐truss structures fabricated via direct laser writing are coated by leveraging planar and inverted cylindrical magnetron cathodes at select deposition rates, sputtering powers, and Ar working pressures. Both plasma focused ion beam and microtome sectioning techniques are employed to evaluate the cross section of individual struts and assess overall uniformity. Overall, the influence of key sputtering factors on the design and development of core–shell composite nano‐ and micro‐lattice materials is highlighted and a pathway for future sputter coating optimization on these complex structures is provided.

Correlation between plasma characteristics, morphology, and microstructure of sputtered CuAl alloy films with varied target geometry

“…To a lesser extent, some studies have investigated ICM sputtering within the cathode volume, analyzing coating wires and adhesion [15,16,[25][26][27]. Furthermore, a few studies have explored this target geometry as an alternate deposition configuration for coating substrates with convoluted complex topologies [16,28,29].…”

“…In general, sputter coated nano-and micro-lattices have mostly employed planar target geometries and focused on the coated lattice material properties; some studies have also investigated coating uniformity and observed thickness gradients resulting from the unidirectional deposition of the planar cathode [31][32][33][34]. Garcia-Taormina et al demonstrated using a hollow cathode that changing target geometry could potentially improve coating coverage on micro-lattice structures by increasing line-of-sight during deposition [28]. Thus, in order to enable further exploration of deposition within complex target geometries, such as the hollow cathode, the correlations between cathode geometry and film growth warrant further research.…”