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

TL;DR

This paper introduces SALAD, a novel hybrid deposition system combining ALD and sputtering, enabling the creation of complex nanocomposites with tailored structures and unique optical properties.

Contribution

The paper presents the design and implementation of SALAD, a new hybrid deposition system that integrates ALD and sputtering within a single chamber for advanced thin film fabrication.

Findings

Successful deposition of AlOx-Cu nanocomposites demonstrating unique optical dispersion.

SALAD system leverages advantages of both ALD and sputtering for complex nanostructures.

Spectroscopic analysis reveals optical properties not explained by conventional theories.

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.