Area-Selective ALD with Soft Lithographic Methods: Using Self-Assembled Monolayers to Direct Film Deposition

Abstract

Area-selective atomic layer deposition (ALD) is a technique that can be used for fabricating 3D structures with dimensions down to the nanoscale. A patterned resist, typically a self-assembled monolayer (SAM), directs film deposition through area-selective ALD, leading to lateral patterning. This article will describe the overall approach to area-selective ALD, introduce the process of atomic layer deposition, and discuss the development of monolayer ALD resists. We will describe the results of studies which show that monolayers with a high degree of packing and hydrophobicity perform best in blocking ALD, and that resistance against ALD can be used as a sensitive probe of SAM quality. We further describe patterning of the SAM through soft lithography, in particular microcontact printing (µCP), for the area-selective ALD process, and compare the area-selective ALD processes for HfO 2 and Pt ALD. The powerful patterning capability of µCP and the flexibility of area-selective ALD for various materials can impact many potential applications, and studies applying this process to fuel cell devices and integrated circuits will be described.

Atomic layer deposited zinc tin oxide channel for amorphous oxide thin film transistors

“…ALD offers the possibility of selective deposition only on some areas while avoiding deposition on other areas that are deactivated, for example, by imprint lithography. 15,16 Thus films can be patterned without any etching step. This patterning process is superior to conventional etching or lift-off in that no coating material is wasted, and no toxic liquid waste (etchant or photo-resist solvent) is created.…”

Review Article: Catalysts design and synthesis via selective atomic layer deposition

“…The area-selective ALD has been applied to fabricate defect-free 3D patterns and nanostructures for electronic applications. 32,33 In catalysis, the motivations of selective-ALD enable directionally and precisely tailoring of the structural parameters, interfaces, and active sites, that is of great significance for advanced catalysis. In this article, fabrication of composite catalysts via selective ALD methods is introduced.…”

Hybrid nanomaterials through molecular and atomic layer deposition: Top down, bottom up, and in-between approaches to new materials

“…This ability has been one of the driving forces in academic research using ALD 25,30 . More recently the surface selectivity of ALD precursors has been used in combination with self-assembled monolayers 38 or through other types of chemical modification of what would otherwise be an inactive surface or substrate 39 forcing deposition in predefined areas and leaving the rest of the substrate more-or-less clean.…”