ECS Transactions:  Near-Room-Temperature Soft Plasma Pulsed Deposition of SiC_x N_y from 1,3,5-tri(isopropyl)cyclotrisilazane

Results are presented from an exploratory study of near-roomtemperature pulsed deposition of SiC_xN_y thin films using 1,3,5- tri(isopropyl)cyclotrisilazane (TICZ, C₉H₂₇N₃Si₃) and soft remote ammonia (NH₃) plasma co-reactants. The process involved four pulses: thermal adsorption of TICZ to the substrate at very low temperature, nitrogen (N₂) purge, soft NH₃ remote plasma step, and N₂ purge. These steps were repeated until the desired film thickness was reached. The ratio of C to N in the films was modulated by controlling the substrate temperature in the range of 30 to 200 °C. In-situ analysis of the deposition process was carried-out using spectroscopic ellipsometry, and the films were analyzed by x-ray photoelectron spectroscopy (XPS). The findings of this study indicate that the combination of reduced substrate thermal budget and soft remote plasma provides an optimum low energy environment for the controlled deposition of SiC_xN_y protective coatings on thermally fragile, chemically sensitive substrates, including plastics and polymers.

Journal of Vacuum Science & Technology B:  Simplified CVD route to near-zero thickness silicon nitride films

Silicon nitride (SiN_x, x ∼ 1) thin films were deposited by chemical vapor deposition on silicon oxide (SiO₂) substrates by combining controlled pulses of the precursor 1,3,5-tri(isopropyl)cyclotrisilazane (TICZ, C₉H₂₇N₃Si₃) with a continuous ammonia (NH₃) plasma. This plasma-assisted pulsed CVD (PPCVD) process enables the integration of the nanoscale thickness and uniformity control achieved in atomic layer deposition with the efficiency of plasma-enhanced CVD (PE-CVD). TICZ was selected because it is a nonpyrophoric stable liquid with a high vapor pressure (∼133 Pa at 70 °C) and could act as a single source for SiN_x with both high Si and N contents. An optimized PPCVD process window was identified consisting of a substrate temperature of 350 °C, a TICZ pulse of ≤0.2 s, and a TICZ purge pulse ≥10 s in a continuous direct NH3 plasma at a NH3 flow rate and a power of 40 SCCM and 3000 W, respectively. The as-deposited films were analyzed by x-ray photoelectron spectroscopy (XPS) and spectroscopic ellipsometry. XPS analysis confirmed the absence of any C inclusion and demonstrated the existence of the 1:1 Si:N ratio. In situ, real-time ellipsometry measurements indicated that SiN_x growth occurred in a typical PE-CVD regime. They also yielded an as-grown SiN_x average refractive index of ∼1.75.

Electronic Materials:  Defect- and H-Free Stoichiometric Silicon Carbide by Thermal CVD from the Single Source Precursor Trisilacyclohexane

Stoichiometric silicon carbide (SiC) thin films were grown using thermal chemical vapor deposition (TCVD) from the single source precursor 1,3,5-trisilacyclohexane (TSCH) on c-Si (100) substrates within an optimized substrate temperature window ranging from 650 to 850 ◦C. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) analyses revealed that the as-deposited films consisted of a Si-C matrix with a Si:C ratio of ~1:1. FTIR and photoluminescence (PL) spectrometry studies showed that films deposited ≥ 750 ◦C were defect- and H-free within the detection limit of the techniques used, while ellipsometry measurements yielded an as-grown SiC average refractive index of ~2.7, consistent with the reference value for the 3C-SiC phase. The exceptional quality of the films appears sufficient to overcome limitations associated with structural defects ranging from failure in high voltage, high temperature electronics to 2-D film growth. TSCH, a liquid at room temperature with good structural stability during transport and handling as well as high vapor pressure (~10 torr at 25 ◦C), provides a viable single source precursor for the growth of stoichiometric SiC without the need for post-deposition thermal treatment

Journal of Biomedical Materials Research:  Characterization and Analysis of Extended-Wear Silicone Hydrogel Contact Lenses Utilizing Novel Silicone Macromers

Contact lenses are one of the most successful biomaterials in history with a global market estimated to be worth over $17 billion in 2025. Silicone hydrogel contact lenses dominate the market and are complex biphasic biomaterials with several critical material properties needed for clinical use. Careful consideration of composition and chemistry is needed to identify formulations of lenses meeting all commercial standards with the potential for improved manufacturability, cost, and/or next generation use. Four silicone macromers were investigated in this work with varying symmetry of siloxane units and macromer structure, number of siloxane groups, branching, length, and concentration. Novel silicone hydrogel lenses were produced and evaluated for optical transmittance, elastic modulus, oxygen transmissibility, water content, and surface wettability. Several lenses met commercial standards and demonstrated an increase in oxygen permeability (Dk) and inverse relationship with elastic modulus and siloxane concentration, respectively. A hydrophobic/hydrophilic ratio below 1.4 was needed for a co-continuous water phase. Substitution of methoxypropyl groups for butyl groups increased hydrophobic microdomains leading to decreased optical quality and mechanical properties. Generally, fluorine-containing silicone macromers allowed for a wider range of successful compositions, and above a certain hydrophilic composition, the presence of trifluoropropyl groups resulted in improved solubility and optically clear lenses. Data also showed asymmetric siloxane macromers have potential to meet critical lens properties at lower overall siloxane content. New lens materials with wider composition ranges meeting all clinical lens properties is a significant challenge and may significantly expand the field.

Organic Process Research & Development:  Organosilanes in Metal-Catalyzed, Enantioselective Reductions

Molecules:  Applications of Hybrid Polymers Generated from Living Anionic Ring Opening Polymerization

Thin Solid Films:  The low-temperature remote-plasma-activated pulsed chemical vapor deposition route to SiNx from 1,3,5-tri(isopropyl)cyclotrisilazane

Personal Care Global:  A CBD Hybrid with Enhanced Flexibility

Vertasil TM-CBD1 (trisiloxanyl-cannabidiol) is a material specifically designed to address the current limitations on CBD use in personal care applications, with an expanded solubility profile to silicone oils and easy integration into silicone gels. This new product is anticipated to enable many applications, including soft skin adhesives, scar reduction treatments, transdermal patches, and anti-wrinkle face masks.

Applied Materials Interface:  Single-Molecule Orthogonal Double-Click Chemistry – Inorganic to Organic Nanostructure Transition – Arkles et al.

Thiasilacyclopentane (TSCP) and azasilacyclopentane (ASCP) heteroatom cyclics reagents can be extended to “simultaneous doubleclicking” when both inorganic and organic substrates are present at the onset of the reaction. The simultaneous double-click depends on a first ring-opening click with an inorganic substrate that is complete in ~1 s at 30 °C and results in the reveal of a cryptic mercaptan or secondary amine group, which can then participate in a second click with an organic substrate.

ECS Journal of Solid State Science and Tech:  Review—Cobalt Thin Films: Trends in Processing Technologies and Emerging Applications

Cobalt metallic films are the subject of an ever-expanding academic and industrial interest for incorporation into a multitude of new technological applications. This report reviews the state-of-the art chemistry and deposition techniques for cobalt thin films, highlighting innovations in cobalt metal-organic chemical vapor deposition (MOCVD), plasma and thermal atomic layer deposition (ALD), as well as pulsed MOCVD technologies, and focusing on cobalt source precursors, thin and ultrathin film growth processes, and the resulting effects on film composition, resistivity and other pertinent properties.

Interface:  Emerging Molecular and Atomic Level Techniques for Nanoscale Applications

This overview provides an introduction and comparison of emerging processing technologies that represent the best contenders to satisfy future demands for ultrathin film applications.

Rubber World:  Soft Tissue Compliant Silicones for Medical Devices

ExSil^® silicone nanocomposites exhibit surprising material properties, such as up to 5,000% stretchability with elastic recovery, the ability to resist tear failure (both initiation and propagation), self-healing/sealing behavior and intrinsically low extractables. As a group, these materials demonstrate an ability to resist and recover from conditions that would normally result in the failure of other elastomers.

Synthesis:  Some Aspects of the Chemistry of Alkynylsilanes – Larson

In amongst the considerable chemistry of acetylenes there lies some unique chemistry of alkynylsilanes (silylacetylenes) some of which is reviewed herein. This unique character is exemplified not only in the silyl protection of the terminal C–H of acetylenes, but also in the ability of the silyl group to be converted into other functionalities after reaction of the alkynylsilane and to its ability to dictate and improve the regioselectivity of reactions at the triple bond. This, when combined with the possible subsequent transformations of the silyl group, makes their chemistry highly versatile and useful.

Paint & Coatings Industry:  Positive Tactile Interaction Coatings – Arkles & Goff

While the sensory appeal of coatings has always been an important driver of consumer acceptance of devices and appliances, positive tactile interaction properties of coatings are gaining increased attention in an industry that has focused primarily on their optical characteristics. Understanding both the aesthetic and functional significance of these tactile characteristics is therefore an area of opportunity. Click here for more information on reactive siloxanes.

Rubber World:  Ultra-high Elongation Silicone Elastomers – Arkles et al.

Silicone elastomers with elongations approaching 5,000%, nearly four times greater than any other commercial elastomer, are now available. These new elastomers utilize a cure mechanism that generates elastomeric properties by driving linear polymers to extremely high molecular weights with concomitant formation of intra- and inter-chain entanglements, rather than covalent crosslinking.  Click here for product information on Gelest ExSil^® 100 (EM2-EX100).

International Fiber Journal:  Gelest Biosafe – Protecting Textiles Safely – Wagner et al.

BIOSAFE^® is a new siliconbased antimicrobial from Gelest, Inc. Its novel activity imparts long lasting bacteriostatic, fungistatic and algistatic properties to substrates, such as textiles, preventing deterioration and discoloration caused by fungi. Furthermore, BIOSAFE^® antimicrobials prevent algae growth and inhibit the growth of odor-causing bacteria.  Click here for more product information on BIOSAFE.