Demonstration of Sputtering Atomic Layer Augmented Deposition (SALAD): Aluminum Oxide-Copper Dielectric-Metal Nanocomposite

Abstract

Designing a thin film structure often begins with choosing a film deposition method that employs a specific primary process by which chemical species are formed and transported. In other words, a film deposition system in which two complementary deposition methods are hybridized should lead to new ways of designing thin film structures with structural complexity tailored at a level that has never been envisioned.This premise inspired us to uniquely combine atomic layer deposition (ALD) and magnetron sputtering (SPU) within a single deposition chamber; the combined film deposition system is referred to as sputtering atomic layer augmented deposition (SALAD). SALAD allows us to take full advantages of both ALDs precise and accurate precursor delivery and SPUs versatility in choices of chemical elements. A SALAD system was designed based on knowledge obtained by computational fluid dynamics with the goal of conceiving a film deposition system that satisfied deposition conditions distinctive for both ALD and SPU, and a prototype SALAD system was assembled by employing off-the-shelf vacuum components.A s a demonstration, the SALAD system was utilized to deposit a unique nanocomposite made of a stack of aluminum oxide thin films by ALD and copper thin films by SPU, AlOx-Cu dielectric-metal (ACDM) nanocomposite thin films, on Si and glass substrates. Spectroscopic reflectivity collected on ACDM nanocomposite thin films shows unique dispersion features to which conventional effective medium theories used for describing optical properties of composites made of a dielectric host that contains metallic inclusions do not seem to simply apply.