(Invited) Electrochemical Atomic Layer Deposition: Metal Deposition One Atomic Layer at a Time Enabled By Potential Pulsing & Self-Limiting Growth

Tuesday, 30 May 2017: 10:00
Marlborough B (Hilton New Orleans Riverside)
R. Akolkar (Case Western Reserve University), Y. Dordi, A. Joi (Lam Research Corporation), K. Venkatraman, and R. Gusley (Case Western Reserve University)
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.