Area-Selective Atomic Layer Deposition Patterned by Electrohydrodynamic Jet Printing for Additive Manufacturing of Functional Materials and Devices

Abstract

There is an increasing interest in additive nanomanufacturing processes, which enable customizable patterning of functional materials and devices on a wide range of substrates. However, there are relatively few techniques with the ability to directly 3D print patterns of functional materials with sub-micron resolution. In this study, we demonstrate the use of additive electrohydrodynamic jet (ejet) printing with an average line width of 312 nm, which acts as an inhibitor for area-selective atomic layer deposition (AS-ALD) of a range of metal oxides. We also demonstrate subtractive e-jet printing with solvent inks that dissolve polymer inhibitor layers in specific regions, which enables localized AS-ALD within those regions. The chemical selectivity and morphology of e-jet patterned polymers towards binary and ternary oxides of ZnO, Al 2 O 3 , and SnO 2 were quantified using X-ray photoelectron spectroscopy, atomic force microscopy, and Auger electron spectroscopy. This approach enables patterning of functional oxide semiconductors, insulators, and transparent conducting oxides with tunable composition, Åscale control of thickness, and sub-μm resolution in the x−y plane. Using a combination of additive and subtractive e-jet printing with AS-ALD, a thin-film transistor was fabricated using zinc−tin-oxide for the semiconductor channel and aluminum-doped zinc oxide as the source and drain electrical contacts. In the future, this technique can be used to print integrated electronics with sub-micron resolution on a variety of substrates.

Is Poly(methyl methacrylate) (PMMA) a Suitable Substrate for ALD?: A Review

“…In this context, the PMMA layer can be eliminated by immersing in organic solvents (dichloromethane [ 84 ], acetone [ 85 , 86 , 87 , 88 , 89 ], isopropanol [ 87 ], or a mixture of acetone and isopropanol [ 87 , 89 , 90 ]), rinsing solvents like methanol [ 86 , 91 ] and finally washed with de-ionized water [ 25 , 84 , 91 ]. Sometimes, the PMMA residues are removed by annealing [ 86 ], Tan et al and Cho et al removed the layer with UV-ozone treatment [ 82 , 92 ]. Figure 19 illustrates practical examples of the various PMMA patterns in AS-ALD.…”

“…TiO 2 ALD and PMMA masked area-selective ALD approach was also explored by the research groups of Sinha [79] and Haider [51]. Cho et al created AS-ALD using PMMA in additive and subtractive printing [82]. Also Wei et al created a passivation hybrid with PMMA and parylene and further coating with AlO x to create thin film transistors [83].…”

“…These patterns are based on the following geometrical shapes: circles [91,93,94], squares [79,91,93,95,96], crosses [97], line(s) [51,82,89], and shapes or draws with more complexity [73,98]. The masking layer, resultant from the PMMA with inhibited growth, can be constituted from TiO 2 [51,79,81,89,91,95], Al 2 O 3 [81,82,98,99], hafnium dioxide (HfO 2 ), zirconium dioxide (ZrO 2 ) [99], and ZnO [73,82,97], SnO 2 [82] Ir, Pt, and Ru [81]. [97]; permission conveyed through Copyright Clearance Center, Inc.); (e) TiO 2 , (republished with permission of (Ashwini Sinha), from [91]; permission conveyed through Copyright Clearance Center, Inc.); (f) HfO 2 , (reprinted from [99] with the permission of AIP Publishing) coatings in a silicon substrate.…”

Atomic Layer Nucleation Engineering: Inhibitor-Free Area-Selective Atomic Layer Deposition of Oxide and Nitride

“…Nowadays, most of the AS-ALD approaches are based on the selective functionalization of GA and NGA by inhibitors. Self-assembled monolayers and polymer-based materials were widely used for the formation of a layer of self-aligned inhibitors on the NGA to block the film growth. − However, the full coverage of inhibitors on NGA takes a long time and an additional step is required to remove inhibitors, which results in selectivity loss and a significant impact on the throughput and yield. The poor thermal stability of inhibitors also imposes process temperature limitation of ALD .…”

Area Selective Deposition of Metal Films Using Temperature Sensitive Masking Materials and Plasma Electrons as Reducing Agents

“…PMMA has recently been used for micro/nano substrate surface pattering using e-jet technique to selectively inhibit material growth for area-selective ALD of ZnO, Al2O3, SnO2, AZO, and ZTO on Si substrates. 23 PDMS can readily be processed into rubbery optically transparent films and is used in a variety of products including contact lenses. PDMS, in the form of free-standing films, can easily be placed where desired on a substrate.…”