Tuesday, 30 May 2017: 10:00
Marlborough B (Hilton New Orleans Riverside)
Many important technological applications, including nano-electronics, photovoltaics and electrocatalysis, critically depend on the ability to fabricate materials with precise, atomic-level control over structure and properties. Traditionally, fabrication of atomic-scale materials has been achieved through vapor-phase atomic layer deposition (ALD); however, this process has several drawbacks such as the use of unstable precursors which decompose yielding contaminated deposits. An alternative approach, using liquid-phase precursors and electrode potential manipulation, termed electrochemical atomic layer deposition (e-ALD), allows atomic-scale deposition of metals such as copper (Cu) and cobalt (Co). In this approach, underpotential deposition first forms a monolayer of a sacrificial metal such as zinc (Zn). The Zn adlayer then undergoes spontaneous surface-limited redox replacement by a nobler metal such as Cu or Co. This sequence is repeated to build multi-layered metal deposits one atomic layer at a time. Unlike vapor-phase ALD, e-ALD does not use unstable precursors and thus provides high-purity deposits. Prior e-ALD formulations have used toxic chemicals and necessitated frequent electrolyte switching; however, our e-ALD approach uses benign chemicals and eliminates electrolyte switching through the use of optimized potential pulsing sequences. This talk will highlight advantages of our e-ALD approach for applications in nano-fabrication and semiconductor interconnect metallization.