Thin film atomic layer deposition equipment for semiconductor processing

Elastomeric primer and adhesive systemSection:ChooseTop of pageElastomeric primer and ad... <<Atomic layer deposition p...Cold cathode vacuum trans...X-ray fluorescence systemPrecision UV mirrorsSolder paste for fine-fea...Process for diamond-like ...Liquid transfer pumpNew literatureEllipsometer for thin-fil...Specialized vacuum gauges...CITING ARTICLES Master Bond X21Med is a single-component elastomeric compound that passes ISO 10993-5 tests for cytotoxicity. It was developed as a primer to promote adhesion between polyolefins and other surfaces such as metals, ceramics, composites, and other kinds of plastics, but it can also bond two polyolefin materials. Easy to use, X21Med has a low viscosity of less than 250 cps. It cures at ambient temperatures; with heat, it cures more rapidly. It is serviceable from −51 °C to 93 °C. As a primer, X21Med should be applied in a thin layer to the surface and then the solvent allowed to evaporate. When used as an adhesive, it should be applied to both substrates and then mated. The maximum area of bonding effectiveness is about 1 inch squared. Once cured, the clear- to light-amber-colored product is tough but not rigid. It is a reliable electrical insulator and has a volume resistivity exceeding 1014 ohm-cm. The compound has applications in medical device, aerospace, electronics, specialty OEM, and other fields. It is available in pints, quarts, gallons, and five-gallon containers. Master Bond Inc, 154 Hobart St, Hackensack, NJ 07601, www.masterbond.com Atomic layer deposition plasma-processing systemSection:ChooseTop of pageElastomeric primer and ad...Atomic layer deposition p... <<Cold cathode vacuum trans...X-ray fluorescence systemPrecision UV mirrorsSolder paste for fine-fea...Process for diamond-like ...Liquid transfer pumpNew literatureEllipsometer for thin-fil...Specialized vacuum gauges...CITING ARTICLES Oxford Instruments has announced the novel FlexAL-2D system for atomic layer deposition (ALD) of 2D transition-metal dichalcogenides for nanodevice applications. The FlexAL-2D system implements plasma-enhanced ALD to synthesize layers of 2D molybdenum disulfide films with tunable morphologies—namely, in-plane and vertically standing nanoscale architectures on CMOS-compatible silicon dioxide and silicon substrates. The wide parameter space offered by the ALD system allows 2D transition-metal dichalcogenides to be grown at lower temperatures than those used in chemical vapor deposition furnaces. With atoms, high temperatures can increase their diffusion on semiconductors and make it harder to place them at the right spot. According to the company, the FlexAL-2D system yields materials of high quality with precise digital thickness control over large-area, 200 mm wafers. Oxford Instruments plc, 300 Baker Ave, Ste 150, Concord, MA 01742, www.oxford-instruments.com Cold cathode vacuum transducerSection:ChooseTop of pageElastomeric primer and ad...Atomic layer deposition p...Cold cathode vacuum trans... <<X-ray fluorescence systemPrecision UV mirrorsSolder paste for fine-fea...Process for diamond-like ...Liquid transfer pumpNew literatureEllipsometer for thin-fil...Specialized vacuum gauges...CITING ARTICLES The MKS Granville-Phillips 523 wide-range cold cathode vacuum transducer is suitable for applications that require an economical cold cathode with limited accuracy for simple, repeatable pressure measurement. It combines diverse materials and two types of discharge. The 523 covers a wide pressure range from 10−7 torr to atmosphere without the use of a conventional heat-loss Pirani sensor. A high-pressure discharge cell makes a second vacuum sensor unnecessary. The device can be mounted in any orientation, has a simple analog output, and complies with Restriction of Hazardous Substances and CE standards. Applications include analytical equipment such as mass spectrometers, scanning electron microscopes, industrial coating systems, and general vacuum-based pressure measurement apparatus. MKS Instruments Inc, 2 Tech Dr, Ste 201, Andover, MA 01810, www.mksinst.com X-ray fluorescence systemSection:ChooseTop of pageElastomeric primer and ad...Atomic layer deposition p...Cold cathode vacuum trans...X-ray fluorescence system <<Precision UV mirrorsSolder paste for fine-fea...Process for diamond-like ...Liquid transfer pumpNew literatureEllipsometer for thin-fil...Specialized vacuum gauges...CITING ARTICLES Bruker has announced its S8 Tiger Series 2 wavelength dispersive x-ray fluorescence (WDXRF) system for advanced quantitative elemental analysis in academic and industrial research and materials quality control. Measurement times are reduced, sample throughput is increased, and time to result is improved, typically by 25% over the previous model. The S8 Tiger Series 2 features XRF2 small spot mapping for detailed maps of elemental distributions in materials. With a 300 µm spot size, XRF2 offers the highest spatial resolution available in WDXRF, according to Bruker. The system introduces the company’s novel HighSense technology, which offers a wide linear dynamic range to enable higher precision levels for process and quality control. The x-ray optics improves sensitivity and spectral resolution to benefit a wide range of applications, including recognition of foreign particles and analysis of material properties in metals, minerals, semiconductors, glass, ceramics, and nanotechnology. Bruker AXS GmbH, Oestliche Rheinbrueckenstr 49, 76187 Karlsruhe, Germany, www.bruker.com Precision UV mirrorsSection:ChooseTop of pageElastomeric primer and ad...Atomic layer deposition p...Cold cathode vacuum trans...X-ray fluorescence systemPrecision UV mirrors <<Solder paste for fine-fea...Process for diamond-like ...Liquid transfer pumpNew literatureEllipsometer for thin-fil...Specialized vacuum gauges...CITING ARTICLES Edmund Optics offers its TechSpec precision UV mirrors in deep-UV (DUV) and new vacuum-UV (VUV) enhanced coatings. They are suitable for use in numerous optical setups to reflect UV light, including fluorescence microscopy and spectrometry, and for various commercially available light sources. The mirrors with DUV coating offer excellent reflection from 190 nm to long-wave IR (LWIR), and the VUV-coated mirrors provide optimized reflection from 120 nm to LWIR. Designed for 0° angle of incidence, TechSpec precision UV mirrors exhibit greater than 78% reflectivity at their specified design wavelength. The mirrors are manufactured from a fused silica substrate and feature aluminum-based coatings for low polarization sensitivity. A surface flatness of λ/10 and a surface quality of 10-5provide for maximum precision. Six models are available in 12.5 mm, 25 mm, and 50 mm diameters. Edmund Optics Inc, 101 E Gloucester Pike, Barrington, NJ 08007-1380, www.edmundoptics.com Solder paste for fine-feature printingSection:ChooseTop of pageElastomeric primer and ad...Atomic layer deposition p...Cold cathode vacuum trans...X-ray fluorescence systemPrecision UV mirrorsSolder paste for fine-fea... <<Process for diamond-like ...Liquid transfer pumpNew literatureEllipsometer for thin-fil...Specialized vacuum gauges...CITING ARTICLES Indium Corp has developed an air and nitrogen reflow, no-clean, lead-free solder paste to meet the fine-feature printing requirements of mobile manufacturers. The Indium11.8HF-SPR (T5-MC) paste is formulated for use with type 5 powder. It delivers high-stencil print-transfer efficiency on a broad range of processes while maintaining high reflow performance, and it is halogen free, per the International Electrochemical Commission’s standard 61249-2-21 test method EN14582. It offers high transfer efficiency through small apertures less than or equal to 0.66 AR and a long stencil life greater than 12 h. Since the paste eliminates hot and cold slump, it inhibits bridging and solder-beading defects. An oxidation barrier avoids the potential for head-in-pillow and graping defects. Indium Corporation, 34 Robinson Rd, Clinton, NY 13323, www.indium.com Process for diamond-like coatingsSection:ChooseTop of pageElastomeric primer and ad...Atomic layer deposition p...Cold cathode vacuum trans...X-ray fluorescence systemPrecision UV mirrorsSolder paste for fine-fea...Process for diamond-like ... <<Liquid transfer pumpNew literatureEllipsometer for thin-fil...Specialized vacuum gauges...CITING ARTICLES By incorporating plasma activation, Intlvac has enhanced the reaction kinetics of its diamond-like carbon (DLC) coating machines that use chemical vapor deposition technology. Coupling a dense plasma to carbon‐based precursor gases creates the favorable reaction energetics needed to form diamond-like material, including tantalum carbide ceramic microstructures. Using the company’s new process recipe, the machines produce hard, wear-and-abrasion-resistant DLC coatings to protect substrates, including temperature-sensitive ones, exposed to harsh environments. The smooth coatings are suitable for low-friction applications. They are chemically inert and appropriate for in situ biomedical uses. The standard Intlvac platform can produce DLC thicknesses from several microns to 10 nm on various substrate materials. Those include silicon, germanium, optical glasses, chalcogenides, sapphire, metals, and plastics. Intlvac Thin Film Corporation, 1401 Duff Dr, Unit 600, Fort Collins, CO 80524, www.intlvac.com Liquid transfer pumpSection:ChooseTop of pageElastomeric primer and ad...Atomic layer deposition p...Cold cathode vacuum trans...X-ray fluorescence systemPrecision UV mirrorsSolder paste for fine-fea...Process for diamond-like ...Liquid transfer pump <<New literatureEllipsometer for thin-fil...Specialized vacuum gauges...CITING ARTICLES KNF has designed an economical solenoid-driven diaphragm pump for OEM users. The FL 10 pump features a nominal liquid flow rate of 100 mL/min against atmospheric pressure, simple linear flow rate adjustment, and a maintenance-free expected lifetime of 10 000 h. It can be operated to 14.5 psig (1 bar). Spring tension in the linear solenoid drive keeps the flow through the FL 10 tight in both directions when turned off and makes additional check valves unnecessary. Built to operate in demanding environments such as wet or dusty areas, the pump has an IP65 protection rating. Sealing between the pump housing and the linear drive ensures safe operation. In case of a ruptured diaphragm, liquid is kept away from other areas of the system. Chemically resistant flow-path materials in the FL 10 allow for reliable transportation of aggressive media. The company’s novel diaphragm technology transports liquid gently, so its pumps can handle sensitive fluids. KNF Neuberger Inc, 2 Black Forest Rd, Trenton, NJ 08691-1810, www.knfusa.com New literatureSection:ChooseTop of pageElastomeric primer and ad...Atomic layer deposition p...Cold cathode vacuum trans...X-ray fluorescence systemPrecision UV mirrorsSolder paste for fine-fea...Process for diamond-like ...Liquid transfer pumpNew literature <<Ellipsometer for thin-fil...Specialized vacuum gauges...CITING ARTICLES Vacuum process monitoring brochure Hiden Analytical has released a brochure on its quadrupole mass spectrometers for vacuum process monitoring. Systems cover the full pressure range from UHV for background species and leak detection to the millibar regime for process monitoring and control. The HPR-30 system addresses the higher-pressure regimes. It features integrated dry vacuum pumping and overpressure protection and is configured to mount directly to the process chamber. The 300 amu mass range is applicable to most process environments, with alternative mass range options available for specialized applications. At lower pressures below 5 × 10−3 millibar, the dual-mode Hiden HMT residual gas analyzer (RGA) uses a Faraday detector for high-pressure operation. It works from low pressures to UHV with electron multiplier detection and offers partial pressure detection sensitivity to 2 × 10−13 millibar. The HALO and HAL RGA series operate at lower-pressure regimes with extensive mass range options up to 1000 amu and minimum detectable partial pressures down to 5 × 10−15 millibar. Hiden Analytical Inc, 37699 Schoolcraft Rd, Livonia, MI 48150, www.hideninc.com Ellipsometer for thin-film measurementsSection:ChooseTop of pageElastomeric primer and ad...Atomic layer deposition p...Cold cathode vacuum trans...X-ray fluorescence systemPrecision UV mirrorsSolder paste for fine-fea...Process for diamond-like ...Liquid transfer pumpNew literatureEllipsometer for thin-fil... <<Specialized vacuum gauges...CITING ARTICLES According to Horiba Scientific, its Uvisel Plus modular ellipsometer includes a new generation of the FastAcq acquisition technology, which can measure thin-film samples faster and more accurately than previously possible. The technology features new electronic data processing and a high-speed monochromator. Samples from 190 nm to 2100 nm can be measured within 3 min at high resolution. The technology allows for continuous adjustment of the spectral resolution along the measurement range. The Uvisel series phase modulation technology can deliver pure, efficient polarization modulation for accurate and sensitive ellipsometric parameter measurements, such as critical thin transparent layers deposited onto glass substrates. The Uvisel Plus is considered a reference ellipsometer for materials science. It is suitable for thin-film thickness and optical constant measurements in materials research and processing, flat-panel displays, microelectronics, and photovoltaics. Horiba Scientific, 3880 Park Ave, Edison, NJ 08820, www.horiba.com Specialized vacuum gauges and controllersSection:ChooseTop of pageElastomeric primer and ad...Atomic layer deposition p...Cold cathode vacuum trans...X-ray fluorescence systemPrecision UV mirrorsSolder paste for fine-fea...Process for diamond-like ...Liquid transfer pumpNew literatureEllipsometer for thin-fil...Specialized vacuum gauges... <<CITING ARTICLES Edwards has released a range of passive gauges and controllers to meet the needs of users with specialized applications in the high-energy physics and UHV fields. The devices are suitable for a wide range of applications, from UHV systems to process industries, and for when an active gauge cannot be used. The passive gauges range from Pirani and Penning gauges to Bayard–Alpert and extractor ion gauge heads. They are used in conjunction with a passive gauge controller to display pressure and serve as an interface. Pressure ranges of 10−9 mbar to 1000 mbar are covered by the PGC201 controller together with Pirani and Penning gauges, and pressure ranges of 10−12 mbar to 1000 mbar are covered by the PGC202 controller together with an integrated Pirani and ion gauge. Edwards, Innovation Dr, Burgess Hill, West Sussex, RH15 9TW, UK, www.edwardsvacuum.com © 2017 American Institute of Physics.

Due to various applications in electronic and optical fields, considerable efforts have been made to develop ZnO based semiconducting materials. ZnO has a wide and direct band gap of 3.37 eV, large exciton binding energy (60 meV), high mechanical and thermal stabilities, and good electrical conductivity. Therefore, ZnO thin films are intensively investigated and applied in solar cells, piezoelectrical devices, gas and biological sensors, catalysts, and high-efficiency short-wavelength optoelectronic nanodevices. To further enhance the properties of ZnO, researchers have been synthesizing ZnO films doped with aluminum or indium. Al doped ZnO (AZO) thin films have been highly developed featuring non-toxicity, low material cost, good thermal stability, high optical transmittance, and good electrical conductivity. [1, 2, 3] Many techniques have been used to deposit AZO thin films currently, such as sol gel processing, magnetron sputtering, pulsed laser deposition (PLD), chemical vapor deposition (CVD), and atomic layer deposition (ALD). Among these film deposition methods, ALD has been extensively investigated for the deposition of thin films of metals, alloys, semiconductors, and oxides. Compared with other techniques, ALD is considered as a novel technique for the deposition of AZO films due to its characteristic feature of self-limiting surface saturating reactions in each ALD cycle. ALD technology consequently and accurately controls the layer thickness with unprecedented atomic level precision, as well as the stoichiometry, composition, uniformity of large areas and maintains excellent conformity over complex surface nanostructures. The other advantage of ALD technology is to introduce each ALD chemical precursor sequentially separated by time to react on the surface of the structure. The concentration of dopant in the ZnO films can be precisely controlled by the number of ALD cycles, so that the physical properties of AZO films, such as carrier density and conductivity, can be adjusted to meet the requirements of different applications. In this study, a Savannah 100 cross-flow thermal ALD reactor was used for the deposition of Al doped ZnO thin films. The precursors of aluminium, zinc and oxygen used in the ALD process for the synthesis of Al doped ZnO thin films were trimethylaluminium (TMA: Al2(CH3)6), diethylzinc (DEZ: (C2H5)2Zn) and DI water. The growth temperature of AZO thin films was maintained at 250 oC. The flow rate of N2, used as a carrier gas, was accurately controlled at 20 sccm. In order to deposit ALD AZO films with various percentages of aluminium, TMA cycles were introduced once in every 30 pulses of DEZ and H2O injection. After deposition, AZO films were annealed in air at 500 oC, 600 oC, and 700 oC for 30 min, respectively. X-ray diffraction (XRD) was performed to characterize the crystal structure of ALD ZnO and AZO films. Field emission scanning electron microscopy (FE-SEM) was used to inspect the morphology of AZO films before and after annealing. The surface roughness was analyzed by atomic force microscopy (AFM). The compositions of AZO thin films were analyzed by energy dispersive X-ray spectroscopy (EDS). The sheet resistivity of AZO films was determined by using four-point probe measurements. Raman spectroscopy and photoluminescence (PL) were used to investigate the properties and detect structures of ALD AZO films. The band gaps of AZO films prepared by the ALD process were analyzed from PL spectroscopy results. The materials property and defect structure of ALD AZO films were investigated by Raman spectroscopy.

Atomic layer deposition (ALD) is a special variant of chemical vapour deposition (CVD) technology used to grow high-quality thin films through alternate self-limiting surface reactions (Figure 4.1). ALD has gained considerable interest in recent years as a thin film deposition method to overcome man...

Atomic layer deposition (ALD) technique is a thin film deposition method that provides highly conformal films on 3D structured supports, including powder materials. The technique relies on sequential self-limiting gas-to-surface reactions which enable control of thin film depositions even down to the atomic level on complex surface geometries. Even if ALD technique has been used in the semiconductor industry in production scale for several years now, there are rather few reports on ALD of battery materials. However, the recent development in processes for lithium containing films clearly opens up new possibilities. Promising applications of ALD include 3D structured all-solid-state batteries and surface modification of electrode powders. The present paper presents an overview of the present status in application of ALD in the field of lithium ion batteries.

As the device dimension continues to shrink, the need for a thinner barrier for copper has risen in order to meet the requirements for future device performance. The conventional barrier process by physical vapor deposition (PVD) has the limitation to achieve conformal step coverage across the dual damascene structure , and therefore would face a bottleneck when the thickness reduction is required. In this work, the atomic layer deposition (ALD) technique is applied for the TaN barrier process of a 90 nm generation copper dual damascene integration with low-k dielectrics of k=3.0. The ALD technique could not only provide a conformal step coverage on both trenches and vias, it could also allows reasonable thickness control for thickness of the order of 10 /spl Aring/. The integration results show that ALD TaN has promising electrical performance on sheet resistance, via resistance, and line-to-line leakage, and it also has superior reliability performance on electromigration, stress migration, and bias temperature test as compared with conventional PVD TaN.

Titanium tetraisopropoxide (TTIP) is a precursor utilized in atomic layer depositions (ALDs) for the growth of TiO2. The chemistry of TTIP deposition onto a slightly oxidized molybdenum substrate was explored under ultrahigh vacuum (UHV) conditions with X-ray photoelectron spectroscopy. Comparison of the Ti(2p) and C(1s) peak areas has been used to determine the surface chemistry for increasing substrate temperatures. TTIP at a gas-phase temperature of 373 K reacts with a MoOx substrate at 373 K but not when the substrate is at 295 K, consistent with a reaction that proceeds via a Langmuir–Hinshelwood mechanism. Chemical vapor deposition was observed for depositions at 473 K, below the thermal decomposition temperature of TTIP and within the ALD temperature window, suggesting an alternative reaction pathway competitive to ALD. We propose that under conditions of low pressure and moderate substrate temperatures dehydration of the reacted precursor by nascent TiO2 becomes the dominant reaction pathway and leads to the CVD growth of TiO2 rather than a self-limiting ALD reaction. These results highlight the complexity of the chemistry of ALD precursors and demonstrate that changing the pressure can drastically alter the surface chemistry.

Atomic layer deposition (ALD) is a technique of choice for a uniform, conformal coating of substrates of complex geometries, owing to its characteristic self-limiting surface reactions upon sequential exposure to precursor vapors. In order to achieve a uniform coating, sufficient gas exposure needs to be provided. This requirement becomes particularly relevant for highly porous and high aspect-ratio substrates, where the gas transport into the substrate structure is limited by diffusion (diffusion-limited regime), or for ALD precursor systems exhibiting a low surface reaction rate (reaction-limited regime). This work reports how the distinction between diffusion- and reaction-limited ALD regimes is directly quantitatively related to the width of the reaction front and the profile of chemisorption coverage in a single-cycle ALD, all of them being determined by the natural length unit of the system. We introduce a new parametrization of the system based on its natural system of units, dictated by the scales of the physical phenomena governing the process. We present a range of scaling laws valid for a general porous substrate, which scale intuitively with the natural units of the system. The scaling laws describe (i) the coating depth in a diffusion-limited regime with respect to the gas exposure, (ii) the chemisorption coverage in a reaction-limited regime with respect to the gas exposure, and (iii) the width of the reaction zone in the diffusion-limited regime. For the first time, the distinction between diffusion- and reaction-limited ALD regimes is directly quantitatively related to the width of the reaction zone and the profile of chemisorption coverage in a single-cycle ALD. The model system for the multicycle diffusion-limited coating of random fibrous mats was validated with an experiment of ALD on a forest of tortuous carbon nanotubes.

Lithium containing multicomponent oxides are important materials for both lithium-ion batteries and optical applications. In most cases thin films of these materials are desired. Atomic layer deposition (ALD) is a thin film deposition method that is known to deposit high quality films by sequential self-limiting surface reactions. However, the reactivity of lithium ions during the deposition process can pose challenges for the control of the film growth and even destroy the self-limiting nature of ALD completely. In this paper, we have studied the combination of atomic layer deposition and solid state reactions for the generation of lithium containing multicomponent oxide films. Atomic layer deposited transition metal oxide thin films were covered with ALD-grown lithium carbonate, and the films were annealed to produce lithium tantalate, titanate, and niobate. Lithium carbonate was chosen as the source of lithium because it is easy to deposit by ALD and can be handled in air. The films were analyzed as-de...

Atomic Layer Deposition (ALD) has garnered significant interest within the scientific community owing to its exceptional ability to deposit ultra-thin films with meticulous control over thickness and uniformity. By capitalizing on self-limited surface reactions, ALD represents a versatile technique for depositing a diverse array of materials encompassing semiconductors, insulators, and metals. However, traditional top-down methodologies, particularly those reliant on lithographic patterning, present inherent complexities characterized by a multitude of process steps, thereby giving rise to challenges such as misalignment, particularly pronounced in intricate three-dimensional (3D) and multilayer structures.In response to these challenges, the emergence of Area-Selective ALD (AS-ALD) heralds a promising paradigm shift towards bottom-up approaches, offering the promising prospect of selective deposition on patterned substrates. The allure of AS-ALD lies in its potential to streamline manufacturing process steps by confining material deposition exclusively within predetermined regions, thereby refining pattern precision while concurrently curtailing process steps. The operationalization of AS-ALD hinges upon the deployment of a non-reactive polymer film as a strategic barrier layer, effectively impeding precursor penetration into undesired regions. In this context, Self-Assembled Monolayers (SAM) are organic monolayers films that are spontaneously formed via complex interactions of van der Waals forces and densely populated on the substrate surface, making them a pivotal component in achieving AS-ALD.SAM, characterized by head, tail, and chain groups, confer a diverse functionality whereby the head group organized substrate reactivity modulation, the tail group modulates penetration of metal precursors into the substrate via end-group manipulation, and the chain group regulates SAM packing density. The strategic harnessing of SAM facilitates selective deposition by impeding precursor diffusion and penetration, thereby endowing a finely calibrated tool for SAM deposition. The controllability of surface properties through modification of molecular structure underscores ALD blocking efficiency as contingent upon factors such as alkyl chain length, with elongated chains fostering augmented Van der Waals attraction and packing density. Generally, empirical evidence substantiates the adequacy of a 12-carbon alkyl chain length for ALD blocking efficacy.A pivotal facet of our investigation revolves around the optimization of SAM coatings on tungsten (W)-deposited silicon (Si) substrates, a crucial endeavor aimed at fortifying substrate adhesion while ensuring seamless compatibility with ALD processes. To this end, phosphonic acid-based SAM materials, boasting the capacity to form up to three bonds with metal surfaces, were judiciously selected to withstand the rigors of high-temperature, low-pressure ALD operations without decomposition. Furthermore, pretreatment of the metal surface with a basic solution served to enhance SAM coating uniformity and coverage, thereby affording a robust processability for subsequent ALD operations. Tailoring the alkyl chain length emerged as an additional aspect, with sophisticated adjustments tailored to fortify SAM coatings against structural degradation, thereby engendering enhanced stability and uniformity. Subsequent heat treatment emerged as a pivotal refinement step, efficaciously optimizing SAM coating uniformity and extending its application range, thereby endowing a versatile toolkit for material deposition.Comprehensive characterization of SAM coatings via a suite of analytical techniques encompassing Atomic Force Microscopy (AFM), Water Contact Angle (WCA) measurements, and X-ray Photoelectron Spectroscopy (XPS) analyses provided invaluable insights into substrate coverage, adhesion, and thermal stability. Quantitative assessments facilitated by frictional force measurements, contact angle analyses, and bond reorganization studies emphasized the efficacy of SAM coatings in facilitating selective ALD, with enhancements in AS-ALD performance attributed to SAM optimization strategies. Collectively, these findings highlight the pivotal role of SAM coatings in advancing the frontiers of AS-ALD technology, offering the imperative optimization strategies in future process developments towards greater efficacy and efficiency.

Atomic layer deposition (ALD) is one of the established techniques among the other chemical and physical deposition techniques of today. There is still, however, a number of challenges for ALD to meet regarding both manufacturing and growth chemistry. The main manufacturing obstacle is the throughput which inherently is low for ALD. In the chemistry side the precursor development plays a very important role together with the understanding of which ALD technique, thermal or plasma enhanced (PE), or even combined (PE)ALD/CVD to use for which application. In the future there will be an increasing need for the development of new ALD materials and for the detailed understanding of the growth of thin films and nanostructures not only on inorganic but also on organic surfaces.

Atomic layer deposition (ALD) of lithium (Li)-based thin films has aroused significant interest in recent years. Promising applications are Li-ion thin-film batteries (TFBs), protective particle coatings, interface model systems, and neuromorphic computing [1,2]. Here, we demonstrate high footprint capacities and excellent high-rate performance of Li4Ti5O12 (LTO) fabricated by ALD for three-dimensional (3D) solid-state TFBs to power upcoming energy-autonomous sensor systems.The simultaneous increase of power and energy density of full-cell 3D TFBs by coating the battery layer stack over microstructured substrates was recently demonstrated [3]. The required conformal, pinhole-free deposition, and stoichiometric control of nanometer-thin films on highly structured surfaces are only accessible via ALD. The vapor-phase technique based on sequential, self-limiting surface reactions is well understood. However, the direct deposition of Li-based anodes remains challenging [1].In previous studies, we developed a thermal three-step ALD process for Li-containing mixed oxides on 200 mm silicon wafers [4, 5]. Lithium-tert-butoxide (LTB) and lithium hexamethyldisilazide (LiHMDS) were proven as suitable precursors, forming high-quality spinel LTO with low impurities after rapid thermal processing. The excellent electrochemical behavior of ALD LTO with LiHMDS was examined and linked to the film texture [5].In this work, we optimize the LTO ALD process with LTB towards high-capacity 3D TFBs and evaluate the electrochemical performance for the first time. A process with tetrakis (dimethylamino) titanium (TDMAT) and H2O at 300 °C was developed, leading to a saturated growth per cycle of 1.06 Å cycle-1 for 7 s LTB pulses. An ALD temperature window between 240 and 320 °C was identified. The effect of the substrate on the initial growth and crystallization behavior was investigated. To overcome the crystallization-inhibiting effect of the titanium nitride current collector, we introduced an ultrathin AlOx interlayer.Planar ALD LTO films with various thicknesses of up to 75 nm were manufactured, increasing the footprint capacity from 1.5 to 4.3 μAh cm-2. We observed a higher surface capacity contribution due to an increased roughness and an inferior C-rate performance with increasing film thickness. 50 nm LTO films demonstrate the optimum energy and power density. A footprint capacity of 1.95 μAh cm-2, corresponding to 67 % of the initial capacity, was achieved at 50 C with an average Coloumb efficiency of 99.9975 %.Next, we evaluate ALD LTO films as 3D TFB anodes for the first time. The conformality of the ALD process on microstructured substrates was improved by extending the LTB pulse and purge times. The purge time is the key factor enabling a step coverage of 70 % for holes with an aspect ratio of 10:1. The 3D samples with an area-enhancement factor (AEF) of 9 coated with 50 nm LTO obtained a footprint capacity of 20.2 μAh cm-2 at 1 C. The significant capacity enhancement of 6.9 compared to planar samples is according to the conformality. The remarkable high-power capability of 3D LTO is demonstrated with 7.75 μAh cm-2 at extreme currents of 5 mA cm-2. A capacity retention of 97.4 % after 500 cycles at 1 mA cm-2 shows the high-rate cyclability. The superior high-rate performance of ALD LTO compared to other 3D anode materials illustrates the enormous potential for realizing high-energy and high-power on-chip 3D TFBs.

Low dislocation density ultraviolet (UV) AlGaN∕GaN multiple quantum well (MQW) structure was grown using atomic layer deposition (ALD) technique. The AlGaN∕GaN MQW grown on the sapphire substrate consisted of three GaN QWs and four AlGaN barriers formed by ALD grown AlN∕GaN superlattices. The as-grown sample showed smooth surface morphology with a root-mean-square roughness value of only 0.35nm, and no surface cracks were found. The dislocation density was estimated to be as low as 3.3×107cm−2. X-ray and transmission electron microscope data showed the MQW had sharp interfaces with good periodicity. The sample had an UV photoluminescence emission at 334nm (3.71eV) with a very narrow linewidth of 47meV at 13K. The cathodoluminescence image revealed a fairly uniform luminescence pattern at room temperature. The AlGaN∕GaN MQW grown by ALD technique should be useful for providing high crystalline quality for fabrication of various optical devices.

Incorporating intermittent renewable energy sources into the power grid will require large amounts of grid-scale energy storage. Electrochemical batteries are a versatile and scalable energy storage option and, hence, Li-ion batteries have been widely adopted to store excess wind and solar energy [1]. Li-ion batteries, however, have a relatively low energy density and serious safety concerns. An alternative electrochemical battery option lies with zinc-air batteries. This technology uses lower cost materials and is overall much safer. Furthermore, zinc-air batteries have a much larger theoretical energy density than Li-ion batteries [2]. The major impediment to wide-scale adoption of zinc-air batteries is the low energy efficiency because of the poor reaction kinetics at the air electrode. Both the charge and discharge reactions at the air electrode are sluggish and require the use of catalysts to obtain practicable performance. However, many catalysts active towards the charge reaction are not active towards the discharge reaction, and vice versa. The development of a catalyst active towards both the charge and discharge reactions, known as a bifunctional catalyst, is therefore a high priority [3]. Furthermore, catalysts employed in zinc-air batteries often show instability, with performance degradation evident after a few cycles. Ultimately, a highly stable bifunctional zinc-air battery catalyst is of the utmost importance.The aim of this work is to develop highly stable bifunctional catalysts for zinc-air batteries using atomic layer deposition (ALD). With ALD, extremely conformal catalyst coatings can be deposited directly on the air electrode of a zinc-air battery. The self-limiting surface reactions of ALD ensure that electrode porosity is maintained while maximizing the total coating surface area [4]. Since ALD operates in the gas phase, catalytic coatings can be deposited deep within the pores of the air electrode. This will help maintain the three-phase boundary necessary for the discharge reaction and ultimately improve the stability of a zinc-air battery [5]. To create a bifunctional catalyst, two ALD processes, one for manganese oxide and another for iron oxide, is combined into one ALD supercycle, depositing a mixed manganese-iron oxide. Since manganese oxide is a well-established discharge catalyst [6], and iron oxide demonstrates activity towards the charge reaction [7], this mixed manganese-iron oxide exhibits bifunctional activity in a zinc-air battery. An optimized supercycle process will be discussed and full-cell battery test results showcased. Specifically, the bifunctional efficiency of a zinc-air battery can be improved by more than 10% by using the mixed manganese-iron oxide catalyst. In addition, the high stability of the manganese-iron oxide catalyst is demonstrated, where bifunctional efficiency can be maintained at over 95% of the initial value over 200 cycles. Materials characterization of the mixed manganese-iron oxide, deposited through ALD, is also included.[1] L. Trahey, F. R. Brushett, N. P. Balsara, G. Ceder, L. Cheng, Y. M. Chiang, N. T. Hahn, B. J. Ingram, S. D. Minteer, J. S. Moore, K. T. Mueller, L. F. Nazar, K. A. Persson, D. J. Siegel, K. Xu, K. R. Zavadil, V. Srinivasan, and G. W. Crabtree, “Energy Storage Emerging: A Perspective from the Joint Center for Energy Storage Research,” Proc. Natl. Acad. Sci. U. S. A., vol. 117, no. 23, pp. 12550–12557, 2020.[2] J. Fu, R. Liang, G. Liu, A. Yu, Z. Bai, L. Yang, and Z. Chen, “Recent Progress in Electrically Rechargeable Zinc – Air Batteries,” Adv. Mater., vol. 31, no. 31, p. 1805230, 2019.[3] E. Davari and D. G. Ivey, “Bifunctional electrocatalysts for Zn – air batteries,” Sustain. Energy Fuels, vol. 2, no. 1, pp. 39–67, 2018.[4] C. Detavernier, J. Dendooven, S. Pulinthanathu Sree, K. F. Ludwig, and J. A. Martens, “Tailoring nanoporous materials by atomic layer deposition,” Chem. Soc. Rev., vol. 40, no. 11, pp. 5242–5253, 2011.[5] M. P. Clark, M. Xiong, K. Cadien, and D. G. Ivey, “High Performance Oxygen Reduction/Evolution Electrodes for Zinc − Air Batteries Prepared by Atomic Layer Deposition of MnOx,” ACS Appl. Energy Mater., vol. 3, no. 1, pp. 603–313, 2020.[6] M. P. Clark, T. Muneshwar, M. Xiong, K. Cadien, and D. G. Ivey, “Saturation Behavior of Atomic Layer Deposition MnOx from Bis(Ethylcyclopentadienyl) Manganese and Water: Saturation Effect on Coverage of Porous Oxygen Reduction Electrodes for Metal-Air Batteries,” ACS Appl. Nano Mater., vol. 2, no. 1, pp. 267–277, 2019.[7] M. Labbe, M. P. Clark, Z. Abedi, A. He, K. Cadien, and D. G. Ivey, “Atomic layer deposition of iron oxide on a porous carbon substrate via ethylferrocene and an oxygen plasma,” Surf. Coatings Technol., vol. 421, p. 127390, 2021.

Supercapacitors are a kind of energy storage device that lie between traditional capacitors and batteries, characterized by high power density, long cycle life, and rapid charging and discharging capabilities. The energy storage mechanism of supercapacitors mainly includes electrical double-layer capacitance and pseudocapacitance. In addition to constructing multi-level pore structures to increase the specific surface area of electrode materials, defect engineering is essential for enhancing electrochemical active sites and achieving additional extrinsic pseudocapacitance. Therefore, developing a simple and efficient method for defect engineering is essential. Atomic layer deposition (ALD) technology enables precise control over thin film thickness at the atomic level through layer-by-layer deposition. This capability allows the intentional introduction of defects, such as vacancies, heteroatom doping, or misalignment, at specific sites within the material. The ALD process can regulate the defects in materials without altering the overall structure, thereby optimizing both the electrochemical and physical properties of the materials. Its self-limiting surface reaction mechanism also ensures that defects and doping sites are introduced uniformly across the material surface. This uniform defect distribution is particularly profitable for high surface area electrodes in supercapacitor applications, as it promotes consistent performance across the entire electrode. This review systematically summarizes the latest advancements in defect engineering via ALD technology in supercapacitors, including the enhancement of conductivity and the increase of active sites in supercapacitor electrode materials through ALD, thereby improving specific capacitance and energy density of the supercapacitor device. Furthermore, we discuss the underlying mechanisms, advantages, and future directions for ALD in this field.

Iridium (Ir) thin films have been extensively investigated for a variety of applications. Ir is a potential optical material for Fresnel zone X-ray microchannel plates, and inductive grid filters. It is also a noble metal making it well suited to corrosion resistance in harsh environments Atomic Layer Deposition (ALD) is considered a special case of chemical vapor deposition (CVD) in that two different chemical precursor materials are alternately introduced into a vacuum chamber where a chemical reaction occurs on the surface of the substrate. This method of thin film growth is self-limiting and conformal and consequently results in precise layer thickness control, stoichiometry, composition, and uniformity across a large surface area. Advantages that are unique to ALD include the ability to grow conformal thin films across complex geometries, and the relatively low temperatures required to achieve film growth. In this work, iridium metal films were synthesized on silicon (Si) and Monel K-500 alloy substrates by ALD using Iridium (III) acetylacetonate known as Ir(acac)3 or [CH3COCH=C(O-)CH3]3 Ir as precursor 1, and industrial grade O2 as oxidizing reactant. The solid Ir precursor was heated to 150 °C, and the substrate temperature was varied to establish an optimum growth window. The lowest temperature in which Ir growth was found is 200 °C, and the thin film growth rate increased as a function of temperature up to 250 °C. Higher temperatures have not yet been attempted due to equipment constraints. The Monel K-500 steel alloy flat discs were cut from commercially available Monel K-500 bars of ~1 inch diameter. In this study we report on the successful synthesis of Ir films on Si and Monel K-500 substrates. Detailed characterization has been performed using X-ray diffraction (XRD) techniques, atomic force microscopy (AFM), and field emission scanning electron microscopy (FE-SEM) of samples which have been notched with focused ion beam (FIB) techniques for cross-sectional film thickness measurements as revealed in Figure 1. The polycrystalline ALD Iridium film exhibited good chemisorption and adhesion to native oxide covered Si substrates, with hydroxyl surface termination. However even with the absence of a SiO2 surface film, the ALD synthesis of Iridium metal films worked equally well on the Monel K-500 steel alloy flat disc substrates and yielded excellent surface coverage.