ASM International (Finland)

Abstract The sources of non‐uniformity in thin films produced using atomic layer deposition (ALD) have been investigated by reviewing the mechanical hardware of ALD reactors, precursors, and the by‐products of surface reactions. The most common causes of non‐uniformity are overlapping pulses, thermal self‐decomposition of precursors, and non‐uniform gas distribution. Less studied, however, are the consequences of downstream surface reactions of gaseous by‐products. In particular, titanium nitride films have been found to be significantly less uniform than those of transition metal oxides deposited from metal halides. The influence of reaction by‐products on the TiN film growth has been studied by comparing the deposition in the cross‐flow and showerhead style reactors. Finally, the sources of non‐uniformity in plasma enhanced (PE) ALD are illustrated by studying the TiN deposition process.

Abstract. Empirical evidence demonstrates that lakes and reservoirs are warming across the globe. Consequently, there is an increased need to project future changes in lake thermal structure and resulting changes in lake biogeochemistry in order to plan for the likely impacts. Previous studies of the impacts of climate change on lakes have often relied on a single model forced with limited scenario-driven projections of future climate for a relatively small number of lakes. As a result, our understanding of the effects of climate change on lakes is fragmentary, based on scattered studies using different data sources and modelling protocols, and mainly focused on individual lakes or lake regions. This has precluded identification of the main impacts of climate change on lakes at global and regional scales and has likely contributed to the lack of lake water quality considerations in policy-relevant documents, such as the Assessment Reports of the Intergovernmental Panel on Climate Change (IPCC). Here, we describe a simulation protocol developed by the Lake Sector of the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP) for simulating climate change impacts on lakes using an ensemble of lake models and climate change scenarios for ISIMIP phases 2 and 3. The protocol prescribes lake simulations driven by climate forcing from gridded observations and different Earth system models under various representative greenhouse gas concentration pathways (RCPs), all consistently bias-corrected on a 0.5∘ × 0.5∘ global grid. In ISIMIP phase 2, 11 lake models were forced with these data to project the thermal structure of 62 well-studied lakes where data were available for calibration under historical conditions, and using uncalibrated models for 17 500 lakes defined for all global grid cells containing lakes. In ISIMIP phase 3, this approach was expanded to consider more lakes, more models, and more processes. The ISIMIP Lake Sector is the largest international effort to project future water temperature, thermal structure, and ice phenology of lakes at local and global scales and paves the way for future simulations of the impacts of climate change on water quality and biogeochemistry in lakes.

Atomic layer deposition (ALD) of silicon nitride (SiNx) is deemed essential for a variety of applications in nanoelectronics, such as gate spacer layers in transistors. In this work an ALD process using bis(tert-butylamino)silane (BTBAS) and N2 plasma was developed and studied. The process exhibited a wide temperature window starting from room temperature up to 500 °C. The material properties and wet-etch rates were investigated as a function of plasma exposure time, plasma pressure, and substrate table temperature. Table temperatures of 300-500 °C yielded a high material quality and a composition close to Si3N4 was obtained at 500 °C (N/Si=1.4±0.1, mass density=2.9±0.1 g/cm3, refractive index=1.96±0.03). Low wet-etch rates of ∼1 nm/min were obtained for films deposited at table temperatures of 400 °C and higher, similar to that achieved in the literature using low-pressure chemical vapor deposition of SiNx at >700 °C. For novel applications requiring significantly lower temperatures, the temperature window from room temperature to 200 °C can be a solution, where relatively high material quality was obtained when operating at low plasma pressures or long plasma exposure times.

This article explores the history of atomic layer deposition(ALD) and its relationship with the American Vacuum Society (AVS). The authors describe the origin and history of ALD science in the 1960s and 1970s. They also report on how the science and technology of ALD progressed through the 1990s and 2000s and continues today. This article focuses on how ALD developed within the AVS and continues to evolve through interactions made possible by the AVS, in particular, the annual International AVS ALD Conference. This conference benefits students, academics, researchers, and industry practitioners alike who seek to understand the fundamentals of self-limiting, alternating binary surface reactions, and how they can be applied to form functional (and sometimes profitable) thin filmmaterials. The flexible structure of the AVS allowed the AVS to quickly organize the ALD community and create a primary conference home. Many new research areas have grown out of the original concepts of “Atomic Layer Epitaxy” and“Molecular Layering,” and some of them are described in this article. The people and research in the ALD field continue to evolve, and the AVS ALDConference is a primary example of how the AVS can help a field expand and flourish.

To keep Moore's law alive, 2D materials are considered as a replacement for Si in advanced nodes due to their atomic thickness, which offers superior performance at nm dimensions. In addition, 2D materials are natural candidates for monolithic integration which opens the door for density scaling along the 3 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rd</sup> dimension at reasonable cost. This paper highlights the obstacles and paths to a scaled 2D CMOS solution. The baseline requirements to challenge the advanced Si nodes are defined both with a physical compact model and TCAD analysis, which allows us to identify the most promising 2D material and device design. For different key challenges, possible integrated solutions are benchmarked and discussed. Finally we report on the learning from our first lab to fab vehicle designed to bridge the lab and IMEC's 300mm pilot line.

We determined relative nitrate‐nitrogen (NO 3 ‐N) loss rates in 100 north‐mid‐European lakes from late spring to summer by using the exponential function N 2 = N 1 e −k(t 2 −t 2 ), where N 1 and N 2 are NO 3 ‐N concentrations at the beginning (t 1 ) and the end (t 2 ) of the time interval, respectively, and k is the specific NO 3 ‐N loss rate. We found that k decreased with increasing lake depth. Adjusting k to the lake depth (k adj ), we observed that k adj was positively related to spring NO 3 ‐N concentrations, but this relationship became insignificant at mean lake depths exceeding 12.5 m. A relationship between k adj and spring NO 3 ‐N concentrations in lakes shallower than 12.5 m implies that changes in spring NO 3 ‐N concentrations influence the NO 3 ‐N loss rate and thereby summer NO 3 ‐N concentrations. Time series from one Estonian, one German, and 14 Swedish lakes shallower than 12.5 m since 1988 revealed that May to August NO 3 ‐N concentrations have decreased over time everywhere, and the number of time periods exhibiting a NO 3 ‐N depleted condition, i.e., NO 3 ‐N levels below 10 mg L −1 , in these lakes has tripled since 1988. We explained the decreasing NO 3 ‐N concentrations by a reduction in external nitrogen loading including atmospheric deposition, and by changes in climate. The observed prolongation of NO 3 ‐N depleted conditions might be one possible explanation for the increasing occurrence of nitrogen‐fixing cyanobacteria in a variety of lake ecosystems.

Abstract Winter is a long period of the annual cycle of many lakes in the northern hemisphere. Low irradiance, ice, and snow cover cause poor light penetration into the water column of these lakes. Therefore, in northern lakes, respiration often exceeds primary production leading to low dissolved oxygen concentrations. This study aimed to quantify under‐ice metabolic processes during winter in an arid zone lake with little snow cover. This study was carried out in a mid‐latitude lake in Inner Mongolia, northern China. The study lake receives relatively high incoming solar radiation on the ice in mid‐winter, and radiation can penetrate down to the bottom sediment as the lake is shallow and the ice lacks snow cover. Primary production and respiration were estimated during two winters using high‐frequency sensor measurements of dissolved oxygen. To quantify under‐ice metabolic processes, sensors were deployed to different depths. During both winters, sensors collected data every 10 min over several weeks. The amount of solar radiation controlled photosynthesis under ice; temperature and photosynthesis together appeared to control respiration. The balance between gross primary production and ecosystem respiration was especially sensitive to changes in snow cover, and the balance between P and R decreased. Our data suggest that photosynthesis by plankton, submerged plants, and epiphytic algae may continue over winter in shallow lakes in mid‐latitudes when there is no snow cover on the ice, as may occur in arid climates. The continuation of photosynthesis under ice buffers against dissolved oxygen depletion and prevents consequent harmful ecosystem effects.

Minimizing power consumption in multi-processor systems requires the use of multiple supplies with a wide range of regulated voltages and currents. Since one inductor per DC-DC converter is expensive, there is an increasing interest in single-inductor-multiple-output (SIMO) DC-DC converters. Recent research results report a SIMO boost converter and various boost or buck converters with two outputs. This 0.5mum CMOS system is a four- output, single-inductor buck converter with independent regulation of each output.

Abstract Interaction of under‐ice physical, chemical, and biological processes with lake ice/snow cover is examined to better understand how changing winter climate may affect lake ecosystems. We derived under‐ice dissolved oxygen (DO) dynamics from high‐frequency observations and modified a widely used lake metabolism model by including the effect of freezing and thawing on DO concentration. Estimates were produced for the production and respiration in a shallow lake on the Mongolian Plateau in three winters. Diel, synoptic, and seasonal variations in DO concentration were detected as responses to solar radiation, episodic snowfall events, and occasional convective mixing. Based on the observations and a radiative transfer model, incident solar radiation was partitioned into reflectance, absorbance, and transmittance by the snow and ice cover. For bare ice, the contributions of these three parts were 35%, 39%, and 26%, respectively, while under a new 4.5 cm thick snow cover, the corresponding values were 79%, 17%, and 3%. This points out the critical role of snow and ice on under‐ice light conditions, which is the primary forcing for the temperature and the rate of photosynthesis under ice. The results showed three principal factors, which influenced under‐ice DO and metabolism: (1) thickness and optical properties of ice and snow, which affected the light transfer and depth of the euphotic zone, (2) mediated radiation and ice‐water heat transfer which controlled water temperature, and (3) DO exclusion during freezing and dilution by melt water. This study highlights the ecosystem characteristics in shallow ice‐covered lakes in arid temperate regions and promotes our understanding of the response of the cold aquatic environment to climate change.

Titanium nitride (TiN) films were deposited using plasma-enhanced atomic layer deposition (PEALD) from the organometallic precursor tetrakis-dimethyl-amino-titanium (TDMAT) with hydrogen () as a coreactant. Low-resistivity values lying from 210 to were achieved for 10 nm thick films deposited at low temperature: . The effects of temperature, plasma time, and plasma power were investigated. It was demonstrated that the chemical reaction is complementary and self-limiting. A minimum energy is necessary to reach the low-resistivity plateau. Chemical and physical properties of the films are also reported and a surface reaction mechanism is proposed. It is suggested that after TDMAT chemisorption to the surface, amines are removed by hydrogen radicals, and at the same time, titanium carbide bonds (Ti–C) are formed. The low resistivity results from the presence of or phases in the PEALD TiN film. The industrial viability of this process was also evaluated on 300 mm wafers. Good performances were obtained on wafer-to-wafer uniformity and step coverage, while some improvements related to the within-wafer uniformity are required.

We show how interfacial oxide engineering in La-doped hafnium zirconate (HZO) ferroelectric (FE) capacitor stacks can be used to significantly improve the ferroelectric response and remnant polarization (P <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">R</inf> ) of the HZO. This is achieved by incorporating either a 1 nm TiO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> seed and/or 2 nm Nb <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> O <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</inf> cap layer in a bilayer (BL) and/or trilayer (TL) configuration with TiN top and bottom electrodes. We show how the Nb <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> O <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</inf> cap is able to facilitate the transition from (anti-FE) tetragonal into (FE) orthorhombic phase by injecting oxygen in the HZO and find that the TiO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> seed layer favorably improves the grain orientation inside the HZO, resulting in a higher 2P <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">R</inf> and reduced wake-up. Finally, depending on the precursors of Hf and Zr that are used, we demonstrate both trilayer devices with an endurance of up to 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sup> cycles with a final 2P <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">R</inf> of ~30μC/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> at 1.8 MV/cm or devices with a record high 2P <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">R,max</inf> of 66.5 μ C/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> after 3× 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sup> cycles at 3 MV/cm.

Adsorptive separation of acetylene (C2H2) from carbon dioxide (CO2) offers a promising approach to purify C2H2 with low-energy footprints. However, the development of ideal adsorbents with simultaneous high C2H2 adsorption and selectivity remains a great challenge due to their very small molecular sizes and physical properties. Herein, we report a lithium(I)-chelation strategy for pore space partition (PSP) in a microporous MOF (Li+@NOTT-101-(COOH)2) to achieve simultaneous high C2H2 uptake and selectivity. The chelation model of Li+ ions within the framework was visually identified by single-crystal X-ray diffraction studies. The immobilized Li+ ions were found to have two functions: (1) partitioning large pore cages into smaller ones while maintaining high surface area and (2) providing specific binding sites to selectively take up C2H2 over CO2. The resulting Li+@NOTT-101-(COOH)2 exhibits a rare combination of a simultaneous high C2H2 capture capacity (205 cm3 g–1) and C2H2/CO2 selectivity (13) at ambient conditions, far surpassing that of NOTT-101-(COOH)2 (148 cm3 g–1 and 3.8, respectively) and most top-tier materials reported. Theoretical calculations and gas-loaded SCXRD studies reveal that the chelated Li+ ions combined with the segmented small cages can selectively bind with a large amount of C2H2 through the unique π-complexation, accounting for the improved C2H2 uptake and selectivity. Breakthrough experiments validated its excellent separation capacity for actual C2H2/CO2 mixtures, providing one of the highest C2H2 productivities of 118.9 L kg–1 (>99.5% purity) in a single adsorption–desorption cycle.

1. Although the intrinsic habitat preferences of a species can be considered to be fixed, the realized habitat use depends on the prevailing abiotic and biotic conditions. Often the core habitats are occupied by dense and stable populations, while marginal habitats become occupied only at times of high density. In a community of interacting species, habitat uses of different species become inter-related, for example an increased density of a strong competitor forcing a weaker competitor to use more marginal habitats. 2. We studied the spatio-temporal distribution patterns of three common small mammal species, the bank vole Myodes glareolus; the field vole Microtus agrestis; and the common shrew Sorex araneus, in a 4-year trapping study carried out on six large islands, each containing a mixture of three main habitat types (forest, field and clear-cut). We experimentally released least weasels (Mustela n. nivalis) to some of the islands to see how the focal species respond to increased predation pressure. 3. Both vole species were largely restricted to their core habitats (bank voles to forests and field voles to fields) at times of low population density. With increasing density, the relative habitat use of both species increased in the clear-cut areas. The common shrew was a generalist in its habitat use at all population densities. 4. The release of the weasels changed the habitat use of all study species. 5. The vole species showed a stronger aggregated pattern than the common shrew, especially at low population density. The vole aggregations remained in the same localities between seasons, except in the case of bank voles after the weasels were released. 6. Bank voles and field voles avoided each other at high density. 7. We conclude that intrinsically differential habitat requirements and flexibility to modify habitat use facilitate the coexistence of the two competing vole species in mosaic landscapes consisting of boreal forests and open habitats.

Abstract Analyses of carbon stable isotopes are often used to estimate the contributions of allochthonous and autochthonous dietary resources to aquatic consumers. Most pelagic food web studies assume that all phytoplankton taxa have a similar δ 13 C value. We studied pelagic food web compartments (dissolved inorganic carbon [ DIC ], phytoplankton, bacteria, seston, cladoceran zooplankton) in 12 small (&lt; 0.1 km 2 ) lakes in southern Finland. These lakes were classified as oligotrophic, mesotrophic, eutrophic, and dystrophic based on their concentrations of total phosphorus and dissolved organic carbon. Additionally, we studied phytoplankton photosynthetic carbon fractionation (ε p ) in laboratory conditions. The photosynthetic fractionation in 28 phytoplankton cultures from nine different phytoplankton classes varied significantly at the class level, and fractionation correlated significantly with the DIC concentration of the growth media. In small boreal lakes, the δ 13 C values of different phytoplankton taxa, as directly measured or estimated from the δ 13 C values of biomarker fatty acids, varied greatly (−18‰ to −44.5‰). Phytoplankton δ 13 C values varied significantly by lake type and were most depleted in dystrophic lakes even though the δ 13 C values of the DIC was similar to mesotrophic lakes. Further within‐taxa variation was found between lakes and between different depths within a lake. Vertical samples from dystrophic lakes also showed lower ε p in the phytoplankton from meta‐ and hypolimnion, possibly as a result of reduced light intensity. Altogether, in nine of the 10 sampled lakes, the δ 13 C values of cladoceran zooplankton were between the minimum and the maximum phytoplankton δ 13 C value of each lake, and thus, phytoplankton alone could explain zooplankton δ 13 C values. We conclude that stable isotope mixing models should take into account carbon variation among different phytoplankton taxa.

The scratch test method is widely used for adhesion evaluation of thin films and coatings. Usual critical load criteria designed for scratch testing of coatings were not applicable to thin atomic layer deposition (ALD) films on silicon wafers. Thus, the bases for critical load evaluation were established and the critical loads suitable for ALD coating adhesion evaluation on silicon wafers were determined in this paper as LCSi1, LCSi2, LCALD1, and LCALD2, representing the failure points of the silicon substrate and the coating delamination points of the ALD coating. The adhesion performance of the ALD Al2O3, TiO2, TiN, and TaCN+Ru coatings with a thickness range between 20 and 600 nm and deposition temperature between 30 and 410 °C on silicon wafers was investigated. In addition, the impact of the annealing process after deposition on adhesion was evaluated for selected cases. The tests carried out using scratch and Scotch tape test showed that the coating deposition and annealing temperature, thickness of the coating, and surface pretreatments of the Si wafer had an impact on the adhesion performance of the ALD coatings on the silicon wafer. There was also an improved load carrying capacity due to Al2O3, the magnitude of which depended on the coating thickness and the deposition temperature. The tape tests were carried out for selected coatings as a comparison. The results show that the scratch test is a useful and applicable tool for adhesion evaluation of ALD coatings, even when carried out for thin (20 nm thick) coatings.

ABSTRACT To assess environmental risks of wood ash, limnological effects of ash application to the drainage basins of two small, humic lakes and one reference lake in southern Finland were examined in this three‐year study. Treated areas corresponded to 12 and 19% of the total catchment and the amount of wood ash added was 6400 kg ha −1 Immediate effects of wood ash on lake water were investigated in three tank experiments each lasting 1.5 wk. In tank experiments, addition of wood ash increased pH, alkalinity, conductivity, and Ca and P concentrations of humic lake water, while growth of phytoplankton decreased. After wood ash application to the subcatchments, pH, alkalinity, conductivity, and concentrations of K + , SO 2− 4 , and Cl − slightly increased, both in inflowing waters and in the lakes, but no increased leaching of Ca, N, or P from the treated subcatchments occurred. Phytoplankton biomass increased in both experimental lakes in comparison with the reference lake. In the lake with 19% application rate to the catchment, zooplankton biomass also increased. The results indicate that, over the short term, a small‐scale ash treatment to a forested drainage basin will not necessarily cause significant changes in the water quality of boreal humic lakes, but at higher application rates, changes in water chemistry and biology are more evident.

) nanodomains, utilizes both transition metals and oxygen redox to yield substantial energy density. However, the inherent heterogeneous nature and distinct nanodomain redox chemistries of layered lithium-rich oxides will inevitably cause pernicious lattice strain and structural displacement, which can hardly be eliminated by conventional doping or coating strategies and result in accelerated performance decay. Herein, we incorporate a strain-inhibiting perovskite phase coherently grown within the layered structure to effectively restrain the displacement and lattice strain during uneven Li-ion extraction. The enhanced mechanochemical stability of the designed cathode benefits the persistent structure and reversible oxygen redox, thereby achieving high initial Coulombic efficiency and stable cycling and voltage profiles. Our approach of lattice engineering alleviates the strain and displacement caused by inhomogeneous reactivity between heterogeneous nanodomains and promotes the development of advanced cathode materials with long durability.

ABSTRACT Effects of light and temperature on growth of two freshwater photosynthetic cryptophytes of different cell size were studied in batch cultures. For the smaller Cryptomonas 979/67, Steele's model and equation of Platt et al. described the relationship between growth rate and photon flux density (PFD), whereas a hyperbolic tangent function gave a better fit for the larger Cryptomonas 979/62. Maximum growth rates given by the three models were consistent with each other, but the hyperbolic tangent function gave slightly lower estimates. Maximum growth rates in relation to temperature were well described for both species by the model of Logan et al. The optimum temperature for growth for Cryptomonas 979/67 was ca. 24.5° C and 19.0° C for Cryptomonas 979/62. The lethal temperatures were 30.4° C and 23.1° C for 979/67 and 979/62, respectively. The estimated maximum growth rates were 1.38 div.·day −1 for Cryptomonas 979/67 and 0.87 div.·day −1 for Cryptomonas 979/62. There were interspecific differences in photoadaptation strategies, as Cryptomonas 979/67 required relatively high PFDs to show net growth, whereas Cryptomonas 979/62 grew at lower irradiances. Cryptomonas 979/67 showed photoinhibition soon after the saturation point, but Cryptomonas 979/62 tolerated a much wider range of irradiance. From their growth responses to light, Cryptomonas 979/ 67 appears to be a stenotopic and Cryptomonas 979/ 62 a eurytopic strain.

The charge transport mechanism through atomic-layer-deposited erbium oxide thin films has been analyzed with current-voltage (I-V) measurements. At low electric field, i.e., below 3 MV/cm, the charge conduction through 10 nm thick Er2O3 films is dominated by Poole–Frenkel electron injection. However, Fowler–Nordheim tunneling of holes also occurs at higher electric fields through the oxide. Various electronic and material parameters such as the trap density, activation energy of the traps, and interface defect density are extracted from the I-V and parallel conductance (GP) measurements as a function of frequency.

The diversity of covalent organic frameworks (COFs) is continuously expanding, providing various materials with tailor-made structures and properties. However, the development of crystalline three-dimensional (3D) COFs with new topologies is an essential but arduous challenge. In this study, we first developed one kind of 3D COFs with the lil topological structure, which were assembled by D4h- and C2h-symmetric building blocks. The 3D COFs were determined in a space group of Imma, in which each D4h-symmetric unit is connected with four C2h-symmetric units, forming a noninterpenetrated network. The densely packed copper phthalocyanine and stable polyimide linkage render these COFs as a polymeric material with high dielectric constant and low dielectric loss at high frequencies (>1 kHz). Significantly, the dielectric constant was determined as high as 63, which constitutes a new record value among phthalocyanine-based and polyimide polymers. Therefore, this study not only provides important guidance for the design of 3D lil-net COFs but also supplies promising materials for application in high-energy-density and pulsed capacitors.