Two-Step Approach for Conformal Chemical Vapor-Phase Deposition of Ultra-Thin Conductive Silver Films

Abstract

Conductive ultra-thin silver films are commonly fabricated by physical vapor deposition methods such as evaporation or sputtering. The line-of-sight geometry of these techniques impedes the conformal growth on substrates with complex morphology. In order to overcome this issue, volume deposition technologies such as chemical vapor deposition or atomic layer deposition are usually preferred. However, the silver films fabricated using these methods are generally non-electrically conductive for thicknesses below 20–50 nm due to island formation. Here, we demonstrate a novel approach for producing ultra-thin conductive silver layers on complex substrates. Relying on chemical vapor-phase deposition and plasma post-treatment, this two-step technique allows the synthesis of highly conductive and uniform silver films with a critical thickness lower than 15 nm and a sheet resistance of 1.6 Ω/□ for a 40 nm-thin film, corresponding to a resistivity of 6.4 μΩ·cm. The high infrared reflectance further demonstrates the optical quality of the films, despite a still large root-mean-square roughness of 8.9 nm. We successfully demonstrate the highly conformal deposition in lateral structures with an aspect ratio of up to 100. This two-step deposition method could be extended to other metals and open new opportunities for depositing electrically conductive films in complex 3D structures.

Thermo-Mechanical Dry Coating as Dry Coating Process is for Pharmaceuticals

“…It's a novel technique that enables synthesizing polymeric film-coat on the FiUlFiP surface 16,17 . The technique results coating of FiUlFiPs with satisfactory uniformity 17,18 . This is with orchestrated topography, surface, and functionalities 15,16 .…”

Dry-Coating of Powder Particles is Current Trend in Pharmaceutical Field

“…It enables synthesising polymeric coating films with an orchestrated surface, topography, and functionalities with satisfactory coating uniformity. Vapour phase deposition is the principle used in methods for achieving vapour coating of powder [57][58][59][60][61] .…”

“…Vapour phase deposition reactions of CVD and ALMD are similar to as both utilises gaseous reagents for nurturing a film [60][61][62][63] . CVD is a single step process.…”

“…While in ALMD, there is split-up of reactions into two surfaces half, it means a twostep reaction 4,64 . This intends, it exposes substrate surface to one reagent only at a time 4,61,62 . As a result of splitting the reaction into two steps, surface will be reacting sequentially with each reagent until complete surface is gets coated by a new atomic-layer 4,62 .…”

“…The reaction is self-limiting thus reaction gets stopped when all totals of surface sites had been transformed back to original surface species 4,62 . At this point, process can be repeating sequentially until wished film thickness is made achievable 4,61 . The process results a monolayer (one complete cycle of A & B) with a film thickness of an order of 1 angstrom (0.1 nano-meters) 4,62 .…”