Lithium fluoride (LiF) is an integral part of UV optics. Recently, it has also gained attention for its role in the solid-electrolyte interphase on the anode of lithium-ion batteries. Atomic layer deposition (ALD) is the preferred tool for synthesizing conformal and pin-hole free LiF thin films, especially on high aspect ratio structures. Present routes to deposit LiF by ALD are based on HF or HF-pyridine

Kinetic modeling has been used to study the decomposition chemistry of ammonia at a wide range of temperatures, pressures, concentrations, and carrier gases mimicking the conditions in chemical vapor deposition (CVD) of metal nitrides. The modeling shows that only a small fraction of the ammonia molecules will decompose at most conditions studied. This suggests that the fact that the high NH3 to metal

Geologic formations provide potentially some of the largest volume capacities for CO2 storage or sequestration. Potential storage sites can be deep saline aquifers, depleted oil reservoirs, and coal seams, surrounded by sealing layers to prevent CO2 from leaking. It is therefore critical to understand mechanisms contributing to CO2 trapping and CO2 leaks. Both phenomena are governed by reactions at

This paper provides an overview of the latest research developments in the design and exploration of ceramic coatings with high temperature adaptive behavior. The adaptive behavior, triggered by thermal or thermomechanical stimulus, may be used to create smart surfaces that are able to change their chemistry and structure to achieve the desired functionality. The initial focus of the paper will be

Continued downscaling of semiconductor devices has placed stringent constraints on all aspects of the fabrication process including plasma-assisted anisotropic etching. To address manufacturing challenges associated with atomic-scale control, material selectivity, etch fidelity, and increasingly complex device architectures, reactive ion etching (RIE) is transitioning to plasma-assisted atomic layer

Influenza results in tens of thousands of deaths annually in the USA and hundreds of thousands worldwide. COVID-19, caused by the SARS-Cov-2 virus, is even more devastating in terms of patient mortality. At the time of this writing, the nanoscopic SARS-Cov-2 virus has paralyzed the world economy and resulted in what are likely permanent changes in our expectations of society and daily life. New technology

Devices based on the unique phase transitions of phase change materials (PCMs) like GeTe and Ge2Sb2Te5 (GST) require low-resistance and thermally stable Ohmic contacts. This work reviews the literature on electrical contacts to GeTe, GST, GeCu2Te3 (GCuT), and Ge2Cr2Te6 (GCrT), especially GeTe due to the greater number of studies. We briefly review how the method used to measure the contact resistance

Recent advancements in β-Ga2O3 materials’ growth and device developments are briefly reviewed with the focus on low-pressure chemical vapor deposition (LPCVD) of β-Ga2O3. β-Ga2O3 films are grown on off-axis c-sapphire and (010) β-Ga2O3 substrates via high-temperature LPCVD (HT-LPCVD) with growth temperatures ranging between 950 and 1050 °C. The effects of HT-LPCVD growth conditions on material properties

Large-area, flexible, two-dimensional transition metal dichalcogenide semiconductor materials (MoS2 and WSe2) were synthesized via magnetron sputtering of amorphous stoichiometric precursor materials on polydimethylsiloxane polymer substrates. Purely amorphous precursor materials and amorphous materials with pre-existing nanocrystalline regions observed via transmission electron microscopy were grown

Two-dimensional (2D) halide perovskites have recently drawn significant interest due to their excellent optoelectronic and photoabsorption properties. Here, we present the large scale synthesis of solution-processed 2D (CH3(CH2)3NH3)2(CH3NH3)n − 1PbnI3n + 1 (n = 2, 3, and 4) perovskites, a family of layered compounds with composition-tunable bandgap, where inkjet printing was used to fabricate heterostructure

To reduce the secondary emission yield of an RF window ceramic so as to suppress the occurrence of a multipactor, we propose coating the window with a titanium nitride (TiN) film by atomic layer deposition. We investigate two groups of samples with film thicknesses of 56 and 8 nm, respectively, to analyze the composition and optimize the coating thickness of the TiN film on the ceramic. For the first

Vanadium dioxide (VO2) thin films were deposited by atomic layer deposition (ALD) using a tetrakis(ethylmethylamino) vanadium precursor and an H2O oxidant at a temperature of 150 °C. Optimization of postdeposition annealing results in smooth, continuous VO2 films (thickness, t ∼ 30 nm) with small grains, exhibiting a transition from semiconducting to metal phase, typically known as the metal-insulator

Atomic layer deposition (ALD) is uniquely capable of providing uniform thin-film coatings on powder substrates, but powder processing has historically required an ALD reactor designed specifically for powders—e.g., a fluidized bed. Tubular hot-walled viscous-flow reactors commonly employed in laboratory-scale ALD research for coating planar substrates such as silicon have been employed previously to

Chalcogenide compounds are leading a revolution in the electronic memories space. Phase-change-memory (PCM) elements and ovonic threshold switches (OTSs) combined in the cross-point (X-point) architecture produce memory arrays with access and write times orders of magnitude faster than state-of-the-art flash nands and also provide nonvolatile storage, a larger scale of integration compared to traditional

One of the important steps in the fabrication of semiconductor memory devices is the deposition of ultrathin silicon nitride films with uniform film thickness and electrical properties. Such high-quality films have made atomic level control during deposition a necessity and can be achieved via atomic layer deposition (ALD) with excellent step coverage. While ALD has been studied experimentally by many

Atomic/molecular layer deposition (ALD/MLD) is strongly emerging as the state-of-the-art gas-phase fabrication technique for novel functional inorganic-organic thin-film materials. In the actual ALD/MLD process development, selecting the proper sublimation temperatures for the inorganic and organic precursors is an important task. In particular, the latter ones tend to require higher sublimation temperatures

We investigated the formation mechanism of interfacially mixed AlSiOx films on Si surfaces under low-energy (<15 eV), high-flux (>4 × 1015 cm−2 s−1) O2+ ion bombardment during Al2O3 plasma-enhanced atomic layer deposition. When high-dose O2+ ions (>1 × 1017 cm−2 cycle−1) were incident on the growing film surface during the oxidation steps in Al2O3 atomic layer deposition (ALD), interfacially mixed

Atomic layer deposition (ALD) is evolving beyond binary compounds to complex oxides and doped structures, taking advantage of the nanometer precision ALD provides. In practice, the development of complex ALD-processes usually means performing many ALD-runs, as success at first attempt is unlikely. One factor at a time methods, where only one factor is altered and the rest are kept constant, are most

Molecular layer deposition (MLD) is able to produce ultrathin polymer films with control over thickness, cross-linking, and chemical composition. With these capabilities, MLD should be useful in the fabrication of novel polymer membranes on porous supports. However, confining a continuous MLD film to the surface of porous substrates is difficult because of MLD film growth in the pores. The deposition

We report on the growth and doping of InAs by atomic layer epitaxy (ALE). The InAs layers were grown using ALE cycles in a metal organic chemical vapor deposition reactor, and Si doping of the films was studied for different SiH4 flow sequences. When SiH4 was added to trimethylindium during the group-III step, the silicon concentration in the film was above 5 × 1019 cm−3. When SiH4 was added to tertiarybutylarsine

Atmospheric-pressure spatial atomic layer deposition (AP-SALD) and atmospheric-pressure spatial chemical vapor deposition (AP-SCVD) are rapid, open-air techniques for the deposition of conformal, pinhole-free films over large areas. In this work, a precursor nebulizer and an ozone generator are incorporated into an AP-SALD system to enable the deposition of tungsten oxide (WO3) films by AP-SCVD. The

Extreme ultraviolet (EUV) lithography has emerged as the next generational step in advancing the manufacturing of increasingly complex semiconductor devices. The commercial viability of this new lithographic technique requires compatible photoresist (PR) materials that satisfy both the lithographic and etch requirements of good feature resolution, chemical sensitivity, a low line edge roughness, and

Thermal atomic layer etching (ALE) of nickel (Ni) may be performed with a step of thin-layer oxidation of its surface and another step of its removal by gas-phase hexafluoroacetylacetone (hfacH) as an etchant. In this study, adsorption of hfacH and possible formation of volatile nickel hexafluoroacetylacetonate Ni(hfac)2 on a NiO surface were investigated based on the density functional theory (DFT)

This article reports the effect of pretreatment with ultrasonic vibration before a plasma treatment onto multiwalled carbon nanotubes (MWCNTs). The pretreatment is supposed to loosen bundled CNTs, enlarging the area to expose the plasma and then increasing the functionalization ratio. Next, the authors conducted a series of experiments to confirm the effect of the pretreatment. The experiment showed

Getting high aspect ratio (HAR) structures is a frequent request in directional etching of silicon using mainstream plasma tools. HAR features are useful either directly (e.g., photonic devices) or as a template for constructing more complicated structures (e.g., metamaterials). The latter is possible by adding postetch procedures such as atomic layer deposition. In this study, a procedure to fabricate

Addition of oxygen was used to control the in-plasma photo-assisted etching (PAE) of p-type Si(100) and poly-Si in a high density, inductively coupled, Faraday-shielded, Ar/Cl2 (225/25 SCCM), 60 mTorr plasma. After etching, samples were transferred under vacuum to an UHV x-ray photoelectron spectroscopy chamber for surface analysis. Samples etched under PAE conditions (ion energies below the ion-assisted

This paper deals with different mechanisms of the interaction of light and heavy low-energy ions with nanoporous structures and main structural changes that occur in these structures under irradiation. The study was carried out using the molecular dynamics method for silicon models with pores of radius of 8 and 28 Å, which are structural analogs of porous films with low dielectric constant (low-k materials)

Our interest in introducing oxygen and/or nitrogen atoms in CH4/H2/Ar plasma mixtures by means of organic precursors in the place of CH4 or by partly substituting O2 or N2O for H2 and thereby controlling carbon deposition and surface passivation when etching HgCdTe under low substrate bias conditions is investigated in this study. Using in situ ellipsometry, in situ x-ray photoelectron spectroscopy

Silver (Ag) film etching was studied with a focus on suppressing the surface roughness induced by Cl2 and CF4 plasmas. After Cl2 plasma etching, roughening of the Ag surface was observed. From in situ x-ray photoelectron spectroscopy and atomic force microscopy analyses using a plasma beam system, the Ag surface was roughened with AgCl formation after Cl2 plasma treatment before exposure to air. In

Epitaxial lattice-matched TiN/(Al,Sc)N metal/semiconductor superlattices have attracted significant interest in recent years for their potential applications in thermionic emission-based thermoelectric devices, optical hyperbolic metamaterials, and hot-electron-based solar-energy converters, as well as for the fundamental studies on the electron, photon, and phonon propagation in heterostructure materials

An oxide layer with a known thickness and chemistry was grown on delta stabilized Pu and sputtered with 1–5 keV Ar+ ions over a range of incident ion angle between 22° and 72°. From the time required to remove the oxide layer, sputter yields of PuO2 were calculated. The sputter yields appear to increase with higher Ar+ ion beam energy in the range of 1–5 keV at an incident sputter ion angle of 42°

In this paper, we demonstrate that the sputtering of solids by ions of low (<30 keV) and even ultralow energies (<2 keV) is accompanied by nonlinear effects. These nonlinear effects are the result of heating a significant part of the cascades of collisions above the effective melting temperature of the material with the formation of local melts or “thermal spots” (a special case of the thermal spike

3D printing offers enormous potential for fabricating custom equipment for space and vacuum systems, but in order to do this at low costs, polymers are necessary. Historically, polymers have not been suitable for these applications because of outgassing, but if coated with a conformal, inorganic film introduced with atomic layer deposition (ALD), then outgassing can be reduced. Previous work on coating

The application of temperature-programmed desorption (TPD) techniques in heterogeneous catalysis to probe, among other things, the nature of the reactions on the surface solid catalyst, and ultimately, the kinetics of desorbed species, is hampered by the inability to make direct observations of adsorbates when they are most catalytically active. Thus, it is almost impossible to make a direct association

Imaging and small-spot (small area) XPS have become increasingly important components of surface chemical analysis during the last three decades, and its use is growing. Some ambiguity in the use of terminology, understanding of concepts, and lack of appropriate reference materials leads to confusing and not always reproducible data. In this paper, it is shown that by using existing knowledge, appropriate

In this work, the structural and mechanical properties of ternary Mo-Al-N alloys are investigated by combining thin film growth experiments and density functional theory (DFT) calculations. Mo1−xAlxNy thin films (∼300 nm thick), with various Al fractions ranging from x = 0 to 0.5 and nitrogen-to-metal (Al + Mo) ratio ranging from y = 0.78 to 1.38, were deposited by direct-current reactive magnetron

The transition in manufacturing from Al(Cu)/W to Cu multilevel on-chip line/via ULSI wiring for high-performance CMOS logic chips was initiated in late 1997 and has since become the exclusive industry-standard. The authors provide a comprehensive review of metal thin-film deposition methods and techniques as they apply to the ULSI of Cu interconnects in advanced logic technology. The authors discuss

Fabrication, optical characterization, and simulation of subwavelength TiO2 hole arrays exhibiting geometry-tunable, omnidirectional color response across the visible spectrum is described. Partially suspended TiO2 grating “membranes” (hole arrays supported by a high void-fraction, low-index underlayer) with quasiperiodic hexagonal order were created on an Si substrate using colloidal lithography,

Sequential cyclic etching of copper thin films was performed using HBr/Ar gas and Ar plasma. The first step involved the formation of CuBrx layers by exposing copper thin films to HBr/Ar gas, and the second step involved the removal of the CuBrx layers by Ar ion sputtering. HBr/Ar gas was used to form the CuBrx layers, and the growth of CuBrx layers could be saturated under certain conditions. Ar ion

The inclusion of plasma in atomic layer deposition processes generally offers the benefit of substantially reduced growth temperatures and greater flexibility in tailoring the gas-phase chemistry to produce specific film characteristics. The benefits plasmas provide, however, come at the cost of a complex array of process variables that often challenge the ability to predict, a priori, the influence

Metal-insulator-metal tunnel junctions (MIMTJs) are an enabling technology for future electronics including advanced computing, data storage, sensors, etc. MIMTJs are formed by inserting an ultrathin insulating layer, known as the tunnel barrier (TB), between metal electrodes. Devices based on MIMTJs have advantages of enhanced quantum coherent transport, fast speed, small size, and energy efficiency

Throughout his career, Dr. Stephen Rossnagel and his co-workers have had a profound influence on thin film deposition. His seminal work includes the development of reactive, collimated, and ionized methods of DC and RF magnetron sputtering, as well as plasma-enhanced atomic layer deposition. Most importantly, his contributions have been widely adopted within the microelectronics community in its efforts

This review offers a succinct overview of the development of a vacuum-compatible microfluidic reactor system for analysis at the liquid vacuum interface (SALVI), and its diverse applications in in situ, in vivo, and in operando imaging of liquid surfaces as well as the air-liquid (a-l), liquid-liquid (l-l), and solid-liquid (s-l) interfaces in the past decade. SALVI is one of the first microfluidics-based

The understanding of fundamental processes in liquids and at the liquid/electrode interfaces of electrochemical systems is crucial for the development of new devices and technologies with higher efficiency and improved performance. However, it is generally difficult to isolate and study the component of interest in such complex systems. Additionally, ex situ analyses do not always reflect the same

We present a perspective on the use of XPS relative peak intensities for determining composition in homogeneous bulk materials. Nonhomogenous effects, such as composition variation with depth or severe topography effects (e.g., in nanoparticles), are not discussed. We consider only the use of conventional laboratory-based instruments with x-ray sources, Alkα or Mgkα. We address accuracy (not precision

X-ray photoelectron spectroscopy (XPS) is widely used to identify chemical species at a surface through the observation of peak positions and peak shapes. It is less widely recognized that intensities in XPS spectra can also be used to obtain information on the chemical composition of the surface of the sample and the depth distribution of chemical species. Transforming XPS data into meaningful information

Two-dimensional layered materials (2DLMs), MoS2 and WS2, and three-dimensional (3D) graphite were infused in thermoplastic polymer matrices comprised of acrylonitrile butadiene styrene (ABS) and polyethylene terephthalate glycol (PETG). Two processing approaches were examined for creating polymer tensile test specimens using the composites for mechanical testing, which included three-dimensional (3D)

The growth of vanadium dioxide (VO2) thin films using tetrakis (ethyl-methyl) amino vanadium (TEMAV) and H2O by atomic layer deposition (ALD) has been investigated as a function of the exposure dose and residence time. A novel multiple pulse mode has been employed to mitigate the small deposition rate brought about by the low vapor pressure of TEMAV. Compared to the conventional ALD cycle with a single

Some extremely reactive metals like Ce, U, and Pu are easily oxidized; instead of forming a stable surface oxide layer preventing further oxidation, the oxide layer break into powders as exposed to air in few days. For nuclear mineral industry, these materials need to be in storage for 1 month or so, which need to minimize surface oxidation. To provide a novel way to storage, atomic layer deposition

Cu2O and CuO are promising p-type semiconductor materials, which show potential for a variety of applications from photovoltaics to high-Tc superconductors. Atomic layer deposition (ALD) presents an advantageous technique for the growth of copper oxide due to the ability to grow on a variety of substrate materials and geometries with atomic precision in thickness and high uniformity. The work presented

The authors produce plasmonic ZnO-TiN nanocomposite films by depositing plasma-synthesized ZnO nanocrystals onto a substrate and then by infilling the nanocrystal network's pores with TiN via remote plasma-enhanced atomic layer deposition (PEALD). This ZnO-TiN nanocomposite exhibits a plasmonic resonance that is blueshifted compared to planar titanium nitride thin films. The authors study the effects

SiO2-Fe2O3 mixture films and nanolaminates were grown by atomic layer deposition from iron trichloride, hexakis(ethylamino)disilane, and ozone at 300 °C. Orthorhombic ɛ-Fe2O3 was identified in Fe2O3 reference films and in Fe2O3 layers grown to certain thicknesses between amorphous SiO2 layers. SiO2-Fe2O3 films could be magnetized in external fields, exhibiting saturation and hysteresis in nonlinear

Area-selective bottom-up synthesis routes of thin films are required to overcome the current limits in lithography, and such growth can be achieved with high quality and nanometer thickness control by area-selective atomic layer deposition (AS-ALD). However, the current range of materials demonstrated deposited by AS-ALD is limited, and no processes for molybdenum oxide have been available so far.

Thin hafnium oxide films were prepared by atomic layer deposition using a carbon-free precursor, tetrakis(tetrahydroborato)hafnium [Hf(BH4)4], and H2O. Film growth was studied using an in situ quartz crystal microbalance and Fourier transform infrared spectroscopy measurements. Self-limiting growth was observed between 100 and 175 °C, but the thermal decomposition of the Hf precursor occurred at higher

This paper investigates manganese-doped zinc oxide (ZnMnO) thin films grown using the atomic layer deposition (ALD) technique. ZnO and MnO layers were deposited alternatively using diethyl zinc and manganese (III) acetylacetonate (Mn(acac)3) as metallic precursors. A suppressed growth rate for both materials was observed during the growth of ZnMnO samples, which is due to reduced adsorption of the

In this work, the authors have investigated the dependence of the anisotropy level in an atomic layer etching (ALE) process of Al2O3 on form factor constraints when the ALE process involves etching in non-line-of-sight locations beneath a silicon nitride mask. In the experiments described here, thermal etching of Al2O3 without the use of any direction-inducing plasma components was explored utilizing

Gallium nitride (GaN) semiconductor devices must be fabricated using plasma etching with precise control of the etching depths and minimal plasma-induced damage on the atomic scale. A cyclic process comprising etchant adsorption and product removal may be suitable for this purpose but an understanding of the associated etching surface reactions is required. The present work examined the formation of

The stringent requirement for patterning highly absorbing metal thin films as a mask for the next-generation extreme ultra-violet lithography system dictates the development of an atomic layer etching process to tailor the etch rate and the etch profile. A “plasma-thermal” atomic layer etching process is developed where an oxygen plasma is used to convert the metallic Ni layer into NiO, followed by

A two-step plasma-thermal atomic layer etching (ALE) process that is capable of etching Ni with high selectivity with respect to the SiO2 hard mask and high anisotropy is evaluated in this work with a reactive ion etching (RIE) process to highlight the contrast between these two processes and the advantages of combining these two processes to tailor the sidewall profile with greater processing efficiency

This work examines the effect of the frequency and peak applied voltage on hydroxyl-radical generation in a dielectric-barrier plasma discharge between a metallic needle electrode and one electrode covered with dielectric. The authors examine a system that can expose up to 96 liquid samples in an automated fashion without human intervention beyond setting the initial software configuration. Then, hydroxyl-radical