Highly Material Selective and Self‐Aligned Photo‐assisted Atomic Layer Deposition of Copper on Oxide Materials

Abstract

There is a growing need for bottom‐up fabrication methods in microelectronic industry as top‐down, lithography‐based methods face increasing challenges. In Photo‐assisted atomic layer deposition (Photo‐ALD), photons supply energy to the deposition reactions on the surface. Here, a process and patterning for Photo‐ALD of copper is reported, with inherently selective, self‐aligned film growth without any photomasking or additive layers. Highly conductive and pure copper films are selectively deposited on tantalum oxide for over hundred nanometers of film thickness, while no copper deposits on silicon or aluminum oxide. On anatase titanium dioxide, copper deposition is crystal‐facet selective. Selective deposition of a metal is realized on oxides, which has been especially challenging for ALD. This study indicates that the growth mechanism is closely related to photocatalysis: the photons interact with the material under the growing copper film, enabling the inherent selectivity. The findings provide promising material engineering schemes for microelectronics, photocatalysis, and photovoltaics.

Photocatalytic setup for in situ and operando ambient-pressure X-ray photoelectron spectroscopy at MAX IV Laboratory

“…Thus, the incorporation of light irradiation replaces the need for two precursors and instead promotes the reaction via photocatalysis. For example, photo-ALD of metal oxides from alkoxides as a single precursor has been an established technique, and it has demonstrated selective ALD by shadow masking (Miikkulainen et al, 2019(Miikkulainen et al, , 2021. The reaction mechanism is most likely similar to those reported by Anderson et al for titanium tetraisopropoxide [Ti(OiPr) 4 ] in a more conventional ALD process: an elimination of the adsorbed isopropoxide releases propene leaving -OH on the surface to react further (Anderson et al, 2013).…”

High‐Performance Graphene‐Dielectric Interface by UV‐Assisted Atomic Layer Deposition for Graphene Field Effect Transistor

“…[ 6 ] In the fabrication of high‐sensitivity GFET devices, the interface property between graphene and the dielectric film is one of the design factors that highly influence device performance. [ 7 ] Therefore, to manufacture such high‐sensitivity GFET‐based sensors, it is essential to deposit a thin and uniform high‐k dielectric film on the graphene surface without the degradation of graphene's superior electrical properties.…”

New Volatile Tantalum Imido Precursors with Carboxamide Ligands

“…Ta 2 O 5 thin films have been fabricated using various methods such as sputtering, electrospray deposition, electron beam evaporation, chemical vapor deposition (CVD), photo-CVD, and atomic layer deposition (ALD). − In particular, ALD is the most advanced technique for the fabrication of thin films because it allows the precise control of the thickness, uniformity over a large area, and conformality, which are requirements for most of the abovementioned applications.…”