@article{nye_carroll_morgan_parsons_2024, title={Vapor-phase zeolitic imidazolate framework-8 growth on fibrous polymer substrates}, volume={42}, ISSN={["1520-8559"]}, url={https://doi.org/10.1116/6.0003183}, DOI={10.1116/6.0003183}, abstractNote={The use of metal-organic frameworks (MOFs) in practical applications is often hindered by synthesis related challenges. Conventional solution-based approaches rely on hazardous solvents and often form powders that are difficult to integrate into practical devices. On the other hand, vapor-phase approaches generally result in MOF films on silicon substrates that make it difficult to characterize the MOF surface area, which is an important quality indicator. We address these challenges by introducing a solvent-free synthesis method to form MOF–fiber composites, which can be more easily integrated into devices. Additionally, these vapor-phase-formed MOF–fiber composites are compatible with Brunauer–Emmett–Teller surface area analysis to characterize MOF quality. Atomic layer deposition is used to form a ZnO film on polypropylene, polyester, and nylon fibrous substrates, which is subsequently converted to zeolitic imidazolate framework-8 (ZIF-8) using 2-methylimidazole vapor. We describe the effects of the ZnO film thickness and MOF conversion conditions on MOF crystallinity and surface area. We report a ZIF-8 surface area of ∼1300 m2/gMOF, which is comparable to reported surface areas of ∼1250–1600 m2/gMOF from conventional synthesis techniques, demonstrating good quality of the solvent-free MOF–fiber composites. We expect these results to extend vapor-phase MOF formation to new, practical substrates for advanced sensing and catalytic applications.}, number={1}, journal={JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A}, author={Nye, Rachel A. and Carroll, Nicholas M. and Morgan, Sarah E. and Parsons, Gregory N.}, year={2024}, month={Jan} }
 @article{kaneda_nye_marques_armini_delabie_setten_pourtois_2023, title={A First-Principles Investigation of the Driving Forces Defining the Selectivity of TiO2 Atomic Layer Deposition}, ISSN={["1932-7455"]}, DOI={10.1021/acs.jpcc.3c00965}, abstractNote={Area-selective deposition (ASD) is a technique to deposit material only on a defined area of a prepatterned surface, while no deposition occurs on adjacent surface areas. It is the subject of intense investigations by the scientific and engineering communities as it offers the prospect to simplify and improve patterning processes for fabrication of nanoelectronic devices as well as to reduce the manufacturing costs. Numerous efforts have been dedicated to identify process conditions for highly selective ASD processes. Still, the search for optimal conditions is often an empirical process due to the limited understanding of the mechanisms that take place at the atomic scale. Understanding the links between precursor reactivity, surface treatments, and the reactor operating conditions could greatly contribute to the development of highly selective ASD processes. In this paper, we therefore combine first-principles calculations with statistical thermodynamics to understand the role of the precursors in area-selective TiO2 atomic layer deposition (ALD). First, we investigate the selectivity loss mechanisms for TiCl4/H2O ALD on SiO2 nongrowth surfaces with different surface terminations (e.g., OH groups and trimethylsilyl groups). We link the resulting thermodynamic driving forces to experimental reports. Subsequently, we extend the investigation to a total of 26 commercially available titanium precursors and to three different oxygen sources and rank their potential for TiO2 ASD for the SiO2 surfaces with different surface terminations (OH groups and trimethylsilyl groups). We find that the combination of TiCl4 with H2O offers the best performance in terms of selectivity. The theoretical approach proposed here is expected to greatly assist and accelerate the design of precursors for different ASD approaches.}, journal={JOURNAL OF PHYSICAL CHEMISTRY C}, author={Kaneda, Yukio and Nye, Rachel A. and Marques, Esteban A. and Armini, Silvia and Delabie, Annelies and Setten, Michiel J. and Pourtois, Geoffrey}, year={2023}, month={May} }
 @article{van dongen_nye_clerix_sixt_de simone_delabie_2023, title={Aminosilane small molecule inhibitors for area-selective deposition: Study of substrate-inhibitor interfacial interactions}, volume={41}, ISSN={["1520-8559"]}, DOI={10.1116/6.0002347}, abstractNote={Area-selective atomic layer deposition (AS-ALD) is a coveted method for the fabrication of next-generation nano-electronic devices, as it can complement lithography and improve alignment through atomic scale control. Selective reactions of small molecule inhibitors (SMIs) can be used to deactivate growth on specific surface areas and as such enable AS-ALD. To investigate new applications of ASD, we need insight into the reactions of SMIs with a broad range of technology relevant materials. This paper investigates the reactions of aminosilane SMIs with a broad range of oxide surfaces and the impact on subsequent atomic layer deposition (ALD). We compare the reactions of two aminosilane SMIs, namely, dimethylamino-trimethylsilane (DMA-TMS) and hexamethyldisilazane (HMDS), with a hydroxylated SiO2 surface and the impact on subsequent ALD processes. The DMA-TMS reaction saturates faster than the HMDS reaction and forms a dense trimethylsilyl (TMS) layer with a higher TMS surface concentration. The higher TMS surface concentration yields better inhibition and higher selectivity during subsequent TiO2 ALD. We show that a wide range of surfaces, i.e., MgO, HfO2, ZrO2, Al2O3, TiO2 (TiN/TiOx), SiO2, SnO2, MoOx, and WO3 remain reactive after DMA-TMS exposure for conditions where SiO2 is passivated, indicating that DMA-TMS can enable AS-ALD on these surfaces with respect to SiO2. On these surfaces, DMA-TMS forms residual TMS and/or SiOxCyHz surface species that do not markedly inhibit ALD but may affect interface purity. Surfaces with lower, similar, and higher surface acidity than SiO2 all show less reactivity toward DMA-TMS, suggesting that surface acidity is not the only factor affecting the substrate-inhibitor interaction. Our study also compares a hybrid inorganic-organic SnOxCyHz and inorganic SnO2 material in view of their relevance as resist for extreme ultraviolet lithography. DMA-TMS can enable selective infiltration in SnOxCyHz, as opposed to selective deposition on SnO2, indicating tunable reactivity by bulk and surface composition. These insights into the reactivity of aminosilane SMIs may aid the design of new area-selective deposition processes, broaden the material space, and enable new applications.}, number={3}, journal={JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A}, author={Van Dongen, Kaat and Nye, Rachel A. A. and Clerix, Jan-Willem J. and Sixt, Claudia and De Simone, Danilo and Delabie, Annelies}, year={2023}, month={May} }
 @article{nye_van dongen_de simone_oka_parsons_delabie_2023, title={Enhancing Performance and Function of Polymethacrylate Extreme Ultraviolet Resists Using Area-Selective Deposition}, volume={2}, ISSN={["1520-5002"]}, url={https://doi.org/10.1021/acs.chemmater.2c03404}, DOI={10.1021/acs.chemmater.2c03404}, abstractNote={Extreme ultraviolet (EUV) lithography is a critical enabler in next-generation technology, although the low etch resistance of conventional organic EUV resists results in low resolution pattern transfer, particularly for smaller features. In this work, we integrate area-selective deposition (ASD), a bottom-up nanopatterning technique, with EUV resists of industrially relevant thicknesses (<50 nm thick) to form resist hardening or tone inverting layers for improved resolution. We utilize TiO2 ASD via atomic layer deposition on 25–35 nm thin photosensitive polymethacrylate-based EUV materials. By tuning the polymer structure and functionality, we enable different scenarios for selective deposition on top of the resist, infiltrated into the bulk resist, or selective to the resist. We find that a cyclohexyl protecting group causes TiO2 inhibition, thus showing promise for tone inversion applications with oxide underlayers. In contrast, resist materials containing a tert-butyl protecting group are good candidates for resist hardening because they enable TiO2 deposition on both EUV exposed and unexposed polymers. Furthermore, we report the integration of a dimethylamino-trimethylsilane inhibitor with the resists to inhibit TiO2 surface nucleation and facilitate subsurface diffusion, thus further broadening potential applications. The results described here establish an important baseline for utilizing ASD on various organic resists to achieve tone inversion or resist hardening and hence improve EUV pattern resolution.}, journal={CHEMISTRY OF MATERIALS}, author={Nye, Rachel A. and Van Dongen, Kaat and De Simone, Danilo and Oka, Hironori and Parsons, Gregory N. and Delabie, Annelies}, year={2023}, month={Feb} }
 @article{nye_van dongen_marneffe_parsons_delabie_2023, title={Quantified Uniformity and Selectivity of TiO2 Films in 45-nm Half Pitch Patterns Using Area-Selective Deposition Supercycles}, volume={6}, ISSN={["2196-7350"]}, DOI={10.1002/admi.202300163}, abstractNote={Abstract}, journal={ADVANCED MATERIALS INTERFACES}, author={Nye, Rachel A. A. and Van Dongen, Kaat and Marneffe, Jean-Francois and Parsons, Gregory N. N. and Delabie, Annelies}, year={2023}, month={Jun} }
 @article{nye_van dongen_oka_de simone_parsons_delabie_2022, title={Compatibility between polymethacrylate-based extreme ultraviolet resists and TiO(2 )area-selective deposition}, volume={21}, ISSN={["2708-8340"]}, DOI={10.1117/1.JMM.21.4.041407}, abstractNote={Abstract. Background Extreme ultraviolet (EUV) lithography is crucial to achieving smaller device sizes for next-generation technology, although organic resists face substantial challenges, such as low etch resistance, which limit the resolution of smaller features. Aim Evaluate the potential for area-selective deposition (ASD) to improve EUV pattern resolution (e.g., by increasing etch resistance). Approach We evaluate thermal compatibility, atomic layer deposition growth rate, and selectivity for TiO2 ASD on various organic EUV resist materials using water contact angle, Rutherford backscattering spectrometry, and X-ray photoelectron spectroscopy. The effects of photo-acid generator (PAG) and EUV exposure on polymer properties and selectivity are considered. Results The organic resist materials studied demonstrate thermal compatibility with TiO2 ALD (125°C for 60 min). The TiO2 ALD process from TiCl4 and H2O proceeds readily on poly(tert-butyl methacrylate), poly(p-hydroxystyrene), and poly(p-hydroxystyrene-random-methacrylic acid) polymers, with and without PAG incorporation, in either the as-formed or EUV exposed state. However, TiO2 is inhibited on poly(cyclohexyl methacrylate). Conclusions We demonstrate that as-formed EUV resists can serve as either the growth or nongrowth surface during TiO2 ASD, thereby enabling resist hardening and tone inversion applications, respectively. These results serve as a basis for further ASD studies on EUV resist materials to improve pattern resolution in next-generation devices.}, number={4}, journal={JOURNAL OF MICRO-NANOPATTERNING MATERIALS AND METROLOGY-JM3}, author={Nye, Rachel A. A. and Van Dongen, Kaat and Oka, Hironori and De Simone, Danilo and Parsons, Gregory N. N. and Delabie, Annelies}, year={2022}, month={Oct} }
 @article{nye_van dongen_oka_furutani_parsons_de simone_delabie_2022, title={Improving polymethacrylate EUV resists with TiO2 area-selective deposition}, volume={12055}, ISBN={["978-1-5106-4985-9"]}, ISSN={["1996-756X"]}, DOI={10.1117/12.2613815}, abstractNote={Extreme ultraviolet (EUV) lithography is crucial to achieving smaller device sizes for next-generation technology, although organic resists face substantial challenges, such as low etch resistance, which limit the resolution of smaller features. Area-selective deposition (ASD) is one potential avenue to improve pattern resolution from organic EUV resists by selectively depositing material on one region of the resist, while preventing material deposition on an adjacent region. We therefore evaluate the compatibility of various organic EUV resists with area-selective atomic layer deposition (ALD) processes, including considering the effects of photo-acid generator (PAG) and EUV exposure on polymer properties and selectivity. The thermal stability of thin resist materials at the TiO2 deposition temperature (125°C for 60 minutes) is confirmed with water contact angle and atomic force microscopy. Upon TiO2 ALD from TiCl4 and H2O, Rutherford backscattering spectrometry reveals successful TiO2 deposition on poly(tert-butyl methacrylate), poly(p-hydroxystyrene), and poly(p-hydroxystyrene-random-methacrylic acid) polymers, regardless of PAG or EUV exposure. However, TiO2 inhibition is observed on poly(cyclohexyl methacrylate). Thus, we demonstrate that EUV polymers can serve as either the growth or non-growth surface during TiO2 ASD, an insight that can be used to enable resist hardening and tone inversion applications, respectively. These results serve as a basis for further ASD studies on EUV resist materials to improve pattern resolution in next-generation devices.}, journal={ADVANCES IN PATTERNING MATERIALS AND PROCESSES XXXIX}, author={Nye, Rachel A. and Van Dongen, Kaat and Oka, Hironori and Furutani, Hajime and Parsons, Gregory and De Simone, Danilo and Delabie, Annelies}, year={2022} }
 @article{nye_song_van dongen_delabie_parsons_2022, title={Mechanisms for undesired nucleation on H-terminated Si and dimethylamino-trimethylsilane passivated SiO2 during TiO2 area-selective atomic layer deposition}, volume={121}, ISSN={["1077-3118"]}, url={https://doi.org/10.1063/5.0106132}, DOI={10.1063/5.0106132}, abstractNote={During TiO2 atomic layer deposition (ALD) using TiCl4 and H2O at ∼150 °C, nucleation proceeds rapidly on hydroxylated SiO2 but is inherently delayed on passivated surfaces such as H-terminated silicon (Si-H) and trimethylsilyl-passivated SiO2 (SiO2-TMS) formed using dimethylamino-trimethylsilane (DMA-TMS) as a small molecule inhibitor. In this work, we explore details of TiO2 nucleation on both Si-H and SiO2-TMS and show that the mechanisms leading to unwanted nuclei depend strongly on the passivation mechanism. Initial growth is observed as a function of ALD cycles using scanning electron microscopy to obtain average particle size, density, and overall surface coverage fraction. Also, average film thickness vs cycle is estimated using ellipsometry or Rutherford backscattering spectrometry. Data are compared to an analytical model that considers that either nucleation sites are present on the starting non-growth surface or sites are generated during the ALD process. On the Si-H surface, data and modeling indicate that nucleation occurs predominantly from a fixed number of nucleation sites present on the starting growth surface that start to immediately grow. However, on TMS-passivated SiO2, nucleation sites are predominantly generated during the growth process so that the density of nucleation sites increases as growth proceeds. Results indicate that nucleation sites are created when adsorbed ALD reactants become kinetically trapped on the SiO2-TMS surface. This demonstrates that mechanisms associated with unwanted nucleation during area-selective deposition (ASD) can depend on details of the surface passivation scheme, thereby providing insight to help to improve ASD strategies for advanced applications.}, number={8}, journal={APPLIED PHYSICS LETTERS}, author={Nye, Rachel A. and Song, Seung Keun and Van Dongen, Kaat and Delabie, Annelies and Parsons, Gregory N.}, year={2022}, month={Aug} }
 @article{nye_wang_uhlenbrock_smythe_parsons_2021, title={In situ analysis of growth rate evolution during molecular layer deposition of ultra-thin polyurea films using aliphatic and aromatic precursors}, volume={51}, ISSN={["1477-9234"]}, url={https://doi.org/10.1039/D1DT03689K}, DOI={10.1039/d1dt03689k}, abstractNote={MLD growth evolution depends on the deposition surface and monomer structure of the deposited film.}, number={5}, journal={DALTON TRANSACTIONS}, publisher={Royal Society of Chemistry (RSC)}, author={Nye, Rachel A. and Wang, Siyao and Uhlenbrock, Stefan and Smythe, John A., III and Parsons, Gregory N.}, year={2021}, month={Dec} }
 @article{matveev_dlott_hanusova_maria_nye_parsons_2020, title={Shock Initiation of Reactive Nanolaminates}, volume={2272}, ISSN={["0094-243X"]}, DOI={10.1063/12.0000877}, abstractNote={The production of heat by reactive nanomaterials occurs at a fuel/oxidizer interface. In order to understand how such materials can be initiated by shock, we studied a model system consisting of a reactive nanolaminate (RNL) with a well-defined planar interface. In addition, an organic thin layer could be intercalated between the fuel and oxidizer to modulate the reaction. We studied a stoichiometric mixture of Zr fuel and CuO oxidizer and the modulator layer was polyurea produced by molecular layer deposition. The RNL was shocked using 0.5 mm diameter Al flyer plates launched by a pulsed laser at 1.5 km/s. We found that little or no reaction was produced immediately under the flyer plate where the interface experiences compression only. Instead the reaction was efficiently initiated by shear waves propagating out from the edges of the flyer plate. The RNL reaction temperature during shock was 4000K, and after the shock dissipated, the RNL reacted at 3000K. Modulator layers caused the reaction to slow down with the effect increasing with increasing modulator thickness up to 500 nm.}, journal={SHOCK COMPRESSION OF CONDENSED MATTER - 2019}, author={Matveev, Sergey M. and Dlott, Dana D. and Hanusova, Petra and Maria, Jon-Paul and Nye, Rachel and Parsons, Gregory}, year={2020} }
 @article{nye_kelliher_gaskins_hopkins_parsons_2020, title={Understanding Molecular Layer Deposition Growth Mechanisms in Polyurea via Picosecond Acoustics Analysis}, volume={32}, ISSN={["1520-5002"]}, url={https://doi.org/10.1021/acs.chemmater.9b04702}, DOI={10.1021/acs.chemmater.9b04702}, abstractNote={Molecular layer deposition (MLD) is an increasingly important thin film synthesis technique in areas such as sensors, microelectronics, protective coatings, and catalysis. However, new analytical a...}, number={4}, journal={CHEMISTRY OF MATERIALS}, publisher={American Chemical Society (ACS)}, author={Nye, Rachel A. and Kelliher, Andrew P. and Gaskins, John T. and Hopkins, Patrick E. and Parsons, Gregory N.}, year={2020}, month={Feb}, pages={1553–1563} }