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The development of new resist materials is vital to fabrication techniques for next-generation microelectronics. Inorganic resists are promising candidates because they have higher etch resistance, are more impervious to pattern collapse, and are more absorbing of extreme ultraviolet (EUV) radiation than organic resists. However, there is limited understanding about how they behave under irradiation. In this work, a Hf-based hybrid thin film resist, known as "hafnicone", is deposited from the vapor-phase via molecular layer deposition (MLD), and its electron-beam and deep-ultraviolet (DUV)-induced patterning mechanism is explored. The hafnicone thin films are deposited at 100 °C by using the Hf precursor tetrakis(dimethylamido)hafnium(IV) and the organic precursor ethylene glycol. E-beam lithography, scanning electron microscopy, and profilometry are used to investigate the resist performance of hafnicone. With 3 M HCl as the developer, hafnicone behaves as a negative tone resist which exhibits a sensitivity of 400 μC/cm

Coordination polymers deposited by hybrid molecular layer deposition (MLD) techniques are of interest as highly conformal, functional materials. Incorporation of a second metal into these coordination polymers can result in additional functionality or fine tuning of the materials properties. Here, we investigate the deposition of multi-metal coordination polymers using hybrid MLD of Zn-Al and Zn-Hf with ethylene glycol as the organic linker. It is found that facile transmetalation occurs for the Zn-Al films, which results in Al-rich films, but does not take place for the Zn-Hf films. Additionally, the Zn-Hf films are found to be more resilient to ambient conditions than the pure Zn-based coordination polymer.

WS(S2)(S2CNEt2)2 has been successfully employed in the aerosol-assisted chemical vapor deposition of WS2 at temperatures above 350 °C. This precursor was found to decompose primarily through the loss of H2S, CS2, and SCNEt. The WS2 deposits were characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, and X-ray diffraction. The deposits exhibited plate-like structures growing vertically from the substrate.

Thermal atomic layer deposition (ALD) of metals on metal oxide surfaces typically suffers from nucleation delays that result in poor-quality films. The poor nucleation may be caused by a lack of suitable chemisorption sites on the oxide surface which are needed for metal nucleation to occur. In this work, we demonstrate that pre-functionalizing the surface with a sub-monolayer of small organometallic molecules from the vapor phase can lead to a significant increase in surface coverage of the metal deposited by ALD. This process is demonstrated for Pt ALD from (methylcyclopentadienyl)trimethylplatinum (MeCpPtMe3) and O2, with nucleation enhanced almost three-fold at 100 ALD cycles after the pre-treatment, and even more significantly at lower ALD cycle numbers. We hypothesize that the high coverage of the organometallic molecule provides an alternative chemisorption mechanism for the platinum precursor and thus leads to an increase in nucleation sites. The growth of the platinum deposits was investigated in depth though scanning electron microscopy (SEM) and grazing incidence small angle x-ray scattering (GISAXS). These studies show that the pre-treatment results in the growth of larger and more highly ordered Pt nanoparticles at early cycle numbers, which subsequently coalesce into continuous and pinhole free films. Surface pretreatment by organometallic molecules therefore introduces a potential route to achieve improved nucleation and growth of ultrathin films.

Tungsten nitrido amido guanidinato complexes of the type WN(NR(2))[(NR′)(2)C(NR(2))](2) (R = Me, Et(;) R’ = (i)Pr, Cy) were synthesized as precursors for aerosol-assisted chemical vapor deposition (AACVD) of WN(x)C(y) thin films. The reaction of tungsten nitrido amido complexes of the type WN(NR(2))(3) (R = Me, Et) with two equivalents of a carbodiimide R′N=C=NR′ (R′ = (i)Pr, Cy) resulted in two insertions of a carbodiimide into W–N(amido) bonds, affording bis(guanidinato) amido nitrido tungsten complexes. These compounds were characterized by (14)N NMR, indicating distinctive chemical shifts for each type of N-bound ligand. Crystallographic structure determination of WN(NMe(2))[(N(i)Pr)(2)C(NMe(2))](2) showed the guanidinato ligands to be non-equivalent. The complex WN(NMe(2))[(N(i)Pr)(2)C(NMe(2))](2) was demonstrated to serve as a precursor for AACVD of WN(x)C(y) thin films, resulting in featureless, X-ray amorphous thin films for growth temperatures 200 – 400 °C.

As one of the most attractive transition metal dichalcogenides (TMDs), the growth of molybdenum disulfide (MoS2) with industrial compatibility is of great importance. Atomic layer deposition (ALD) has been shown to be a promising method to achieve the growth of high-quality TMD materials. However, MoS2 films deposited by ALD often are amorphous with nonideal stoichiometry and require high-temperature post-deposition annealing. In this study, we introduce a modified ALD recipe using Mo(CO)6 and H2S, resulting in controllable linear growth behavior, a S-to-Mo ratio of 2:1, and crystalline films at a temperature as low as 190 °C. The growth mechanisms and key factors leading to this improvement are proposed and complemented by kinetics calculations. This newly developed methodology relies on aligning the process time with the reaction kinetics of carbonyl disassociation. The MoS2 films prepared herein were shown to be active hydrogen evolution reaction catalysts.

The photothermal heating of plasmonic metal nanostructures can be exploited for bottom-up nanofabrication via surface plasmon-mediated chemical solution deposition (SPMCSD). Herein, we demonstrate the versatility of this plasmon-mediated strategy with a rapid deposition (t ≈ 5 min) of metallic copper nanoparticles (Cu NPs) on a silver (Ag) film on nanosphere (AgFON) substrate under low-power, visible-light irradiation (I0 = 2.0 W/cm2, λ > 435 nm). The resultant plasmonic nanostructures exhibit significant optical extinction and enriched chemical affinity for Raman probe molecules, rendering the hybrid AgFON/Cu substrate a suitable plasmonic platform for chemical sensing via surface-enhanced Raman scattering (SERS).

Atomic layer deposition (ALD) is a powerful tool for achieving atomic level control in the deposition of thin films. However, several physical and chemical phenomena can occur which cause deviation from "ideal" film growth during ALD. Understanding the underlying mechanisms that cause these deviations is important to achieving even better control over the growth of the deposited material. Herein, we review several precursor chemisorption mechanisms and the effect of chemisorption on ALD growth. We then follow with a discussion on diffusion and its impact on film growth during ALD. Together, these two fundamental processes of chemisorption and diffusion underlie the majority of mechanisms which contribute to material growth during a given ALD process, and the recognition of their role allows for more rational design of ALD parameters.

First row transition metal complexes (Ni, Co, Cu, Zn) with N,N-disubstituted-N′-acylthiourea ligands have been synthesized and characterized. Bis(N,N-diisopropyl-N′-cinnamoylthiourea)nickel was found to have the lowest onset temperature for thermal decomposition. Thin film deposition of Ni, Co, and Zn sulfides by aerosol assisted chemical vapor deposition from their respective N,N-diisopropyl-N′-cinnamoylthiourea complexes at 350 °C has been demonstrated.

A critical step involved in many applications of one-dimensional seeded CdSe@CdS nanorods, such as luminescent solar concentrators, optical gains, and photocatalysis, is the localization of excitons from the light-harvesting CdS nanorod antenna into the light-emitting CdSe quantum dot seed. We report that the rod-to-seed exciton localization efficiency decreases with the rod length but is independent of band alignment between the CdSe seed and CdS rod. This universal dependence can be well modeled by the competition between exciton one-dimensional diffusion to the CdSe seed and trapping on the CdS rod. This finding provides a rational approach for optimizing these materials for their various device applications.