Uniform Surface Characteristics in Sequentially Polymerized Polyurea Films

Choi, U Hyeok; Kim, Hyein; Park, Yiseul; Lee, Jin Seok

doi:10.1002/bkcs.11344

Cited by 5 publications

(4 citation statements)

References 20 publications

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“…The two materials are referred to as PDIC/ED and PDIC/HD, respectively. A range of diamines has been previously used for polyurea MLD, including 1,4-butylenediamine and p -phenylenediamine . To the best of our knowledge, this is the first study of PDIC/HD MLD. ,,, Results from intermixing standard and novel MLD chemistries and analysis techniques allow us to draw new conclusions about MLD growth mechanisms.…”

Section: Introductionmentioning

confidence: 96%

Understanding Molecular Layer Deposition Growth Mechanisms in Polyurea via Picosecond Acoustics Analysis

et al. 2020

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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 approaches are needed to advance fundamental understanding of deposition reaction mechanisms. This work introduces ultrafast laser-based pump–probe picosecond acoustics analysis to characterize thickness-dependent properties of MLD films. Polyurea films are deposited on hydroxylated SiO2 substrates using 1,4-phenylene diisocyanate and a diamine reactant, either ethylenediamine (PDIC/ED polymer) or 1,6-hexanediamine (PDIC/HD), and the expected polymer structure is confirmed by Fourier transform infrared spectroscopy. During the first ∼20 nm of deposition, spectroscopic ellipsometry shows constant refractive index but decreasing growth rate before reaching steady state. X-ray reflectivity also shows approximately constant density during initial growth. However, the measured picosecond acoustics signatures demonstrate a marked increase in sound speed initially, indicating a transition in the physical film structure. The observed trends are ascribed to a transition in the kinetics of active site production and termination with increasing thickness, leading to changes in polymer and oligomer connectivity within the film. These findings provide a basis for better understanding MLD processes and reaction mechanisms that determine deposited film properties.

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Section: Introductionmentioning

confidence: 96%

Understanding Molecular Layer Deposition Growth Mechanisms in Polyurea via Picosecond Acoustics Analysis

et al. 2020

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“…Several options for diamine precursors include ethylenediamine (ED), 37 1,6-hexanediamine (HD), 34 1,4-diaminobutane, 38 and p-phenylenediamine. 39 However, the diisocyanate reactant is typically limited to p-phenylene diisocyanate (PDIC) for polyurea 20,35 and polyurethane 40 MLD. PDIC is not an ideal precursor because it is a solid at RT (melting point ∼97.5 °C) with a low vapor pressure (<0.01 mmHg at 20 °C), so that valves and gas delivery lines require careful temperature control to avoid condensation.…”

Section: Introductionmentioning

confidence: 99%

In situ analysis of growth rate evolution during molecular layer deposition of ultra-thin polyurea films using aliphatic and aromatic precursors

et al. 2022

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“…New organic components have also been developed for the purely organic MLD processes; the MLD material library already includes, besides the initially introduced polyimides [15,[17][18][19][20][21][22][137][138][139][140][141][142][143] and polyamides, [15,[23][24][25][26][27][28][144][145][146][147][148][149] many other polymers: polyurea, [29,30,37,38,51,[150][151][152][153][154][155][156][157][158][159][160][161][162][163][164] polythiourea, [52] polyurethane, [165,…”

Section: Organic Precursors In Ald/mldmentioning

confidence: 99%

“…New organic components have also been developed for the purely organic MLD processes; the MLD material library already includes, besides the initially introduced polyimides [ 15,17–22,137–143 ] and polyamides, [ 15,23–28,144–149 ] many other polymers: polyurea, [ 29,30,37,38,51,150–164 ] polythiourea, [ 52 ] polyurethane, [ 165,166 ] polyazomethine, [ 167–172 ] poly(3,4‐ethylenedioxy‐thiophene), [ 173–177 ] polyimide–polyamide, [ 141 ] poly(ethylene terephthalate) (PET), [ 50,178–180 ] and others. [ 31,32,39–44,176,181–200 ] In recent years, the organic precursor library has been rapidly expanding.…”

Section: Organic Precursors In Ald/mldmentioning

confidence: 99%

Atomic/Molecular Layer Deposition for Designer's Functional Metal–Organic Materials

Multia

Karppinen

2022

Adv Materials Inter

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organic ligands act as bridges between the metal centers to form infinite 1D, 2D, or 3D structures. These materials are often referred to as coordination polymer (CP) [1] or metal-organic framework (MOF) [2] materials; the latter term is used when the metal-organic material is crystalline and highly porous. [3] The research field of CP-and MOF-type materials has grown tremendously over the last two decades. The structural and chemical diversity of these materials has served as a continuous source of scientific excitement; the same diversity has also triggered huge technological interest as these materials possess enormous potential to be tailored for a wide variety of applications ranging from gas capture, storage, and separation to sensing, catalysis, optics, electronics, and energy storage. [4][5][6][7] Most of the targeted application breakthroughs of metal-organics require that these materials can be produced as highquality thin films and coatings, which can be integrated with the other components in the actual device configuration. The possibility to deposit such thin films in an industry-feasible manner on the substrate types needed, would be a major step forward in the field. [8] Traditionally, solvent-based processes such as liquid-phase epitaxy, Langmuir-Blodgett, layer-by-layer, and electrochemical deposition techniques have been used for metal-organic thin films. [9][10][11] These are, however, incompatible with the requirements set by the possible integration of the materials in microelectronics. This is due to corrosion and contamination risks, and the problems in patterning and precise deposition on high-aspect-ratio features. Hence, it is vital to develop solventfree thin-film deposition routes for the metal-organic material family. In the optimal case, these deposition methods should allow conformal coatings on large-area and high-aspect-ratio substrates.The currently strongly emerging ALD/MLD technique is uniquely suited to address the challenge in a scientifically elegant yet industrially feasible way. This technique is derived from the two parent gas-phase thin-film techniques: ALD for inorganic materials (mostly binary metal oxides, sulfides, and nitrides), [12][13][14] and its counterpart MLD for purely organic thin films (e.g., polyimides and polyamides). [15] In both cases, the attractive film growth characteristics are derived from the unique way of separating the different precursor gas pulses. Currently, ALD is the standard thin-film technology in many Atomic layer deposition (ALD) for high-quality conformal inorganic thin films is one of the cornerstones of modern microelectronics, while molecular layer deposition (MLD) is its less-exploited counterpart for purely organic thin films. Currently, the hybrid of these two techniques, i.e., ALD/MLD, is strongly emerging as a state-of-the-art gas-phase route for designer's metal-organic thin films, e.g., for the next-generation energy technologies. The ALD/MLD literature comprises nearly 300 original journal papers covering most of the alkali...

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Uniform Surface Characteristics in Sequentially Polymerized Polyurea Films

Cited by 5 publications

References 20 publications

Understanding Molecular Layer Deposition Growth Mechanisms in Polyurea via Picosecond Acoustics Analysis

Understanding Molecular Layer Deposition Growth Mechanisms in Polyurea via Picosecond Acoustics Analysis

In situ analysis of growth rate evolution during molecular layer deposition of ultra-thin polyurea films using aliphatic and aromatic precursors

Atomic/Molecular Layer Deposition for Designer's Functional Metal–Organic Materials

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