High-energy Ion Bombardment Research Articles

Effect of Ion-Assisted Deposition Energy of RF Source on Optical Properties, Microstructure, and Residual Stress of HfO2 Thin Films

HfO2 thin films were prepared using radio frequency (RF) ion source-assisted deposition, and the effects of auxiliary ion energy on the microstructure, optical properties, and residual stress of the films were systematically studied. The experimental results showed that when the auxiliary ion energy increased, the extinction coefficient, compressive stress, and optical band gap were gradually increased. These changes were attributed to increased grain boundary defects, crystal structure disorder, and grain size decrease due to high-energy ion bombardment. The HfO2 films deposited at a lower ion energy (600 V) exhibited higher surface quality (RMS = 0.78 nm), better optical properties (k = 10⁻5), and lower residual stress (1.26 GPa).

Foreign Body Reaction to Ion-Beam-Treated Polyurethane Implant.

All artificial materials used for implantation into an organism cause a foreign body reaction. This is an obstacle for a number of medical technologies. In this work, we investigated the effect of high-energy ion bombardment on polyurethane for medical purposes and the reaction of body tissues to its insertion into the mouse organism. An analysis of the cellular response and shell thickness near the implant showed a decrease in the foreign body reaction for implants treated with high-energy ions compared to untreated implants. The decrease in the reaction is associated with the activation of the polyurethane surface due to the formation on the surface layer of condensed aromatic clusters with unbonded valences on the carbon atoms at the edges of such clusters and the covalent attachment of the organism's own proteins to the activated surface of the implant. Thus, immune cells do not identify the implant surface coated with its own proteins as a foreign body. The deactivation of free valences at the edges of aromatic structures due to the storage of the treated implant before surgery reduces surface activity and partially restores the foreign body response. For the greatest effect in eliminating a foreign body reaction, it is recommended to perform the operation immediately after treating the implant with high-energy ions, with minimal contact of the treated surface with any materials.

Effect of arc deposition process on mechanical properties and microstructure of TiAlSiN gradient coatings

In order to successfully prepare a new advanced TiAlSiN gradient coating with Ti content gradually decreased but Al content gradually increased from the cemented carbide substrate to the outermost coating surface by arc ion plating, we deeply investigated the influence mechanisms of two important process parameters. These parameters include substrate bias voltage and arc current, which affect the mechanical properties and microstructure of the gradient coating. The results show that bias voltage and arc current directly affect the particle accumulation effect on the coating surface and the re-sputtering effect caused by high-energy ion bombardment, thus affecting the deposition efficiency of the coating and the formation of defects such as macro-particles and pits on the coating surface. The increase of bias voltage is conducive to the increase of the density of columnar crystals and nanocrystals. While the increase of arc current makes the coating with high Al content transform from columnar crystals to nanocrystals. The hardness and interfacial adhesion of the gradient coatings showed a tendency of firstly increasing and then decreasing with the increase of both bias voltage and arc current. When the bias voltage and arc current are -80 V and 160 A respectively, the coating has the best mechanical properties, its surface hardness reaches 36.94 GPa, and the interfacial adhesion exceeds 120 N. In addition, with the increase of bias voltage and arc current, particles are deposited on the surface of the coating with higher energy, which leads to the preferential orientation transition from (111) to (200) plane. The high hardness of TiAlSiN coating is mainly due to the formation of high Al content of fcc-TiAlN crystals and amorphous Si3N4 in the gradient-coated surface layer. The results have important theoretical and practical significance for developing new high-performance gradient coating tools.

Sputtered Sn-doped Ga2O3 films under balance controlled of energy supply and ion bombardment for solar-blind detection application

The characteristics of amorphous Sn-doped Ga2O3 films deposited using radio frequency magnetron sputtering at room temperature under different sputter powers have been demonstrated. A balance mechanism of energy supply and ion bombardment controlled by sputter power has been found during the deposition. The increasing growth rate as power can be due to the increased yield sputtering species indicated by an in situ optical emission spectroscopy. As the power increases to 700 W, an obvious change from discrete nanoparticles to flat-continuous film can be observed because of sufficient energy supply for oxidation reaction, which leads to the maximum ratio of lattice oxygen and Sn4+ indicating the optimal film quality and conductive property. However, a non-negligible high energy ion bombardment presented at 900 W leads to the degraded film quality. The influence of sputtering power on Sn-doped Ga2O3 solar-blind photodetectors is demonstrated. It can obtain a good performance with an ultra-low dark current density of 2.2 × 10−11 A/cm2, a substantial light-dark current ratio of 1.08 × 103 and fast rise/decay time of 1.59 s/0.54 s at 700 W. The revelation of the role of sputtering power on the properties of Sn-doped Ga2O3 films may offer an interesting direction for low-cost and high-performance solar-blind photodetectors.

Thinning of Poly(methyl methacrylate) and Poly(vinyl chloride) Thin Films Induced by High-Energy Ions of Different Stopping Powers.

Ion bombardment is an important tool of materials processing, but usually leads to erosion of the surface and significant thickness reductions when thin layers are used. The growing use of polymer thin films in a variety of applications, from coatings and membranes to biomedical and electronic devices, calls for a deeper understanding of the thinning process induced by energetic ions espe-cially for very thin films. Here, thinning and surface morphology changes induced by high-energy ion bombardment in PMMA and PVC thin films were investigated, focusing on the role of the initial thickness of the films and the stopping power of the ions. We used thin films with initial thicknesses varying from 13 to 800 nm, and light and heavy ions as projectiles in the energy range of 2-2000 MeV, where the electronic stopping dominates. Thickness reductions as a function of fluence were monitored and thinning cross sections were extracted from curves. A supralinear scaling between the thinning cross sections and the electronic stopping power of the beams was observed, with a much enhanced thinning efficiency for the swift heavy ions. The scaling with the stopping power dE/dx is almost independent of the initial thickness of the films. At intermediate and large fluences, changes in the physicochemical properties of the irradiated polymers may modulate and decelerate the thinning process of the remaining film. The importance of this secondary process depends on the stopping power and the balance between erosion and the chemical transformations induced by the beam. We also observe a trend for the thinning efficiency to become larger in very thin films. Depending on the type of beam and polymer, this effect is more or less pronounced. PMMA films irradiated with 2 MeV H+ show the most systematic correlation between initial thickness and thinning cross sections, while in PVC films the initial thickness plays a minor role for all investigated beams.

Modulation of structure and corrosion behavior of Si-DLC coatings on AZ31 by applying a self-source bias

The Si-DLC coating was fabricated on AZ31 via a dual system consisting of a self-source bias and a meshed plasma immersion deposition, where the incident ion energy can be modulated by the self-source bias. The structure was characterized using field emission scanning electron microscope, transmission electron microscope, Raman spectroscopy, and Fourier transform infrared spectroscopy. The corrosion behavior was evaluated using an electrochemical workstation. The utilization of the bias significantly densifies the coating structure, producing a nano-sized SiC phase and elevating its corrosion resistance. Notably, the −500 V bias coating exhibits superior short-term corrosion resistance. Interestingly, the high-energy ion bombardment produced by the high bias induces carbon diffusion in the coating, leading to the formation of a nano-ceramic TiC interface, which further enhances the corrosion resistance of the Si-DLC coating. Moreover, the increase in bias is accompanied by a decrease in surface porosity, hydrogen content, and sp2/sp3 ratio. In addition, the mechanisms involved in the formation of the TiC nano-interface and the corrosion resistance of the coating are analyzed and explained. A modulated approach to enhance the corrosion resistance of Si-DLC coatings and provide protection against magnesium alloys is achieved by dense structures resulting from high-energy ion bombardment.

High-Density Nanopatterning of SiGeAsTe Chalcogenide as Ovonic Threshold Switch Selectors for Memory Applications

Cross-point memory architecture involves high-density, fast yet cost-effective storage class memories (SCM). As a result, ovonic threshold switches (OTS) are extensively researched as they are needed in series with the SCM-based memory element for its precise functioning. In addition, these OTS-based devices exhibit the potential to be self-selecting memories too. Hence, its integration-friendly patterning becomes pivotal for large-scale manufacturing. Chalcogenide-based alloys are often the desired candidate for OTS. Here, we study the patterning of one of the widely investigated chalcogenide alloys─SiGeAsTe. While the elements of the alloy generate highly volatile halogenated etch by-products, this material is also prone to severe etch-induced lateral undercuts and material damage. Thus, its high-density patterning is challenging. A conventional method to minimize this undercut damage is to increase the hydrocarbon passivation during the etch process to prevent the exposure of the chalcogenide’s sidewalls (SWs) to any type of etchant. Inherently, this leads to the tapering of the OTS-based pillars, consequently becoming an impediment to their scaling at tighter pitches. Here, we clearly establish that OTS-based devices with well-preserved chemical and morphological properties can be fabricated using lower hydrocarbon passivation by tuning the ion energies during etching. Higher ion energies ensure better etch directionality. Concurrently, a well-controlled high energy ion bombardment is likely to enhance deposition of the passivating hydrocarbon from the etch front on to the chalcogenide’s SWs. This is achieved without any unwanted redeposition from underlying layers in the OTS-based stack. We successfully demonstrate high-density nanopatterning of chalcogenide-based OTS devices of diameter ∼65 nm at 200 nm wide pitch. This is also effectively reproduced on 300 mm semiconductor wafers. The electrically measured devices exhibit low leakage and high endurance. This distinctive yet uncomplicated etch tailoring is also discussed to be scalable for pitches <200 nm and for other chalcogenide compositions.

Improvement of the uniformity of structural and electrical properties of transparent conductive Al-doped ZnO thin films by inductively coupled plasma-assisted radio frequency magnetron sputtering

Transparent conductive Al-doped Zinc oxide thin films were deposited on glass substrates by conventional radio frequency magnetron sputtering (C-RFMS) and inductively coupled plasma-assisted radio frequency magnetron sputtering (ICP-RFMS) methods. The structural and electrical properties of films were studied as a function of the radial position (r) of the substrate in both methods. A good thickness uniformity was obtained in ICP-RFMS, while a significant decrease in film thickness was observed at r=30mm (erosion zone) in C-RFMS. The c-axis orientation was achieved in all positions in ICP-RFMS, while crystallinity was degraded at r≥25mm in C-RFMS. Low resistivity ρ of the order of 10−4Ωcm was obtained at all positions in ICP-RFMS, while ρ was rapidly increased at r≥30mm in C-RFMS. In ICP-RFMS, high-energy ion bombardment is suppressed due to the modified plasma density profile and lower space potential. As for transparency, the sample prepared at r=0mm in ICP-RFMS showed an average visible transmittance of 81%, higher than that in C-RFMS. Throughout the study, it was demonstrated that ICP-RFMS method was promising to improve the radial distribution of structural, electrical, and optical properties of Al-doped ZnO thin films.

Characterization of an Etch Profile at a Wafer Edge in Capacitively Coupled Plasma.

Recently, the uniformity in the wafer edge area that is normally abandoned in the fabrication process has become important for improving the process yield. The wafer edge structure normally has a difference of height between wafer and electrode, which can result in a sheath bend, distorting important parameters of the etch, such as ionic properties, resulting in nonuniform etching. This problem nowadays is resolved by introducing the supplemented structure called a focus ring on the periphery of the wafer. However, the focus ring is known to be easily eroded by the bombardment of high-energy ions, resulting in etch nonuniformity again, so that the focus ring is a consumable part and must be replaced periodically. Because of this issue, there are many simulation studies being conducted on the correlation between the sheath structural characteristics and materials of focus rings to find the replacement period, but the experimental data and an analysis based on this are not sufficient yet. In this study, in order to experimentally investigate the etching characteristics of the wafer edge area according to the sheath structure of the wafer edge, the etching was performed by increasing the wafer height (thickness) in the wafer edge area. The result shows that the degree of tilt in the etch profile at the wafer edge and the area where the tilt is observed severely are increased with the height difference between the wafer and electrode. This study is expected to provide a database for the characteristics of the etching at the wafer edge and useful information regarding the tolerance of the height difference for untilted etch profile and the replacement period of the etch ring.

Real-time time-dependent DFT study of laser-enhanced atomic layer etching of silicon for damage-free nanostructure fabrication

Atomic layer etching (ALE) has emerged as a promising technique that enables the manufacturing of atomically controlled nanostructures toward next-generation nanoelectronics. However, the high-energy ion bombardment (typically 40–60 eV for Si) in current plasma ALE would cause damage to structures and even underlying substrates, which is detrimental to processing controllability as well as device performances. This problem could be addressed by introducing an additional laser source into the plasma ALE process to reduce the required ion energy, namely, laser-enhanced ALE. To elucidate the fundamental role of photons in laser-enhanced ALE, we explored the laser–matter interaction in laser-enhanced ALE of Si using real-time time-dependent density functional theory. The results show that with time evolution the incident laser would produce repulsive forces between the modified and bulk Si atoms. The magnitude of these forces can be up to 1.94 eV/Å when a large laser intensity and a short wavelength are employed. Under such large forces, the corresponding bonds are weakened with electron distribution decreasing significantly and can be even broken directly as time propagates. Low-energy ions can, therefore, be used to selectively remove the modified Si atoms whose bonds are already weakened by the additional laser, thereby minimizing and even eliminating the unwanted surface damage.

Self-driven carbon atom implantation into fullerene embedding metal–carbon cluster

Hundreds of members have been synthesized and versatile applications have been promised for endofullerenes (EFs) in the past 30 y. However, the formation mechanism of EFs is still a long-standing puzzle to chemists, especially the mechanism of embedding clusters into charged carbon cages. Here, based on synthesis and structures of two representative vanadium-scandium-carbido/carbide EFs, VSc2C@Ih (7)-C80 and VSc2C2@Ih (7)-C80, a reasonable mechanism-C1 implantation (a carbon atom is implanted into carbon cage)-is proposed to interpret the evolution from VSc2C carbido to VSc2C2 carbide cluster. Supported by theoretical calculations together with crystallographic characterization, the single electron on vanadium (V) in VSc2C@Ih (7)-C80 is proved to facilitate the C1 implantation. While the V=C double bond is identified for VSc2C@Ih (7)-C80, after C1 implantation the distance between V and C atoms in VSc2C2@Ih (7)-C80 falls into the range of single bond lengths as previously shown in typical V-based organometallic complexes. This work exemplifies in situ self-driven implantation of an outer carbon atom into a charged carbon cage, which is different from previous heterogeneous implantation of nonmetal atoms (Group-V or -VIII atoms) driven by high-energy ion bombardment or high-pressure offline, and the proposed C1 implantation mechanism represents a heretofore unknown metal-carbon cluster encapsulation mechanism and can be the fundamental basis for EF family genesis.

Synthesis of nanocrystalline diamond embedded diamond-like carbon films on untreated glass substrates at low temperature using (C2H2 + H2) gas composition in microwave plasma CVD

Diamond-like carbon (DLC) films with well distinguished nanocrystalline diamond (NCD) grains embedded in the matrix are grown at ∼300 °C on glass substrates without any pre-treatment, using a specially-designed stainless-steel shadow-mask assembly creating diffuse secondary plasma that shields the growth zone from high energy ion bombardment. The effects of different compositions of the precursor gas, R = C2H2 / (C2H2 + H2), and gas pressure in the plasma at 500 W of microwave power demonstrate their significant influences on controlling the relative composition of the sp3 to sp2 hybridized carbon phases in the films. The maximum intensity ratio of IDia/IG (∼1.05) and IDia/ID (∼1.05) along with the corresponding minimum of ID/IG (∼1.0) appearing in the Raman spectrum at R = 0.33 and 25 Torr pressure, correlate a superior diamond-phase containing ∼55% sp3-hybridized carbon in the DLC network having high optical transmittance of ∼87% at 600 nm wavelength. A homogeneous microstructure with uniform distribution of the NCD grains of average size ∼10 nm and 〈111〉 crystallographic orientation, and smooth surface morphology with average roughness ∼2.1 nm is obtained in the optimum NCD embedded DLC film, the growth mechanism of which is discussed on the basis of parametric changes.

Microstructure, Mechanical and Antibacterial Properties of TiNb-Based Alloy Implanted by Silver Ions

In this study, in order to obtain an antibacterial property for the TiNb-based alloy, the metal vapor vacuum arc (MEVVA) ion implantation technology was applied to implant the silver on the surface of TiNb-based alloy, which brought the change of the microstructures and mechanical properties for the surface of substrate. It was found that the diffusely distributed silver nanoparticles generated on the outermost surface of the implanted layer and the Ag element exist as a solid-solution state in the implanted layer. Meanwhile, the region of the implanted layer mainly constituted nanocrystalline structures based on the analyses of microstructures. Hence, the nanocrystalline strengthening effect formed by high-energy ion bombardment and the solid solution strengthening effect of silver atoms made contributions to the increase of surface comprehensive mechanical properties, including the surface hardness and elastic modulus. Finally, the suitable Ag-implanted specimen can obtain excellent antibacterial ability. Except for the antibacterial mechanism of silver ions release, the dispersed silver nanoparticles on the surface also provide the contact antimicrobial mechanism, which is the Schottky barrier–dependent antimicrobial efficacy of silver nanoparticles.

Plasma-enhanced atomic layer deposition of titanium molybdenum nitride: Influence of RF bias and substrate structure

In this work, TiMoN thin films were deposited by plasma-enhanced atomic layer deposition with an equal number of Ti and Mo precursor exposures at a substrate temperature of 250 °C. Tetrakis(dimethylamido) titanium and bis(tert-butylimido)bis(dimethylamido) molybdenum were used as sources for Ti and Mo, respectively. N2 and N2/H2 plasma were used, respectively, for TiN and MoN cycles as a source for N. Negative RF substrate bias voltage of magnitude, |Vbias|, of 0, 31, 62, 125, and 188 V were applied during the plasma half cycle. Nanocrystalline rock salt crystal structures were found by x-ray diffraction for films deposited on single-crystal Si and Si-thermal oxide substrates. Applying |Vbias| generated voids by the bombardment of high-energy ions, lowering the density. Further increase of |Vbias| caused the annihilation of voids and a slight increase in density. Four-point probe measurement showed increased electrical resistivity due to a reduction in grain size caused by continuous renucleation during growth. High-energy ions at high |Vbias| sputtered away the films resulting in low growth rates. Stripe test revealed inferior wear rates and coefficients of friction at higher |Vbias| due to low-density porous films. Epitaxial films deposited on c-plane sapphire had (111) orientation and considerable mosaicity with twinned domains rotated at 60° to each other.

Chemical Dopant‐Free Doping by Annealing and Electron Beam Irradiation on 2D Materials

AbstractDoping is a key technique for forming complementary metal‐oxide‐semiconductor (CMOS) that is a basic building block for current state‐of‐the‐art semiconductor devices. However, conventional doping methods such as ion implantation are unsuitable for 2D materials due to their ultra‐thinness to accommodate substitutionally doped atomic structures and vulnerability to high energy ion bombardment. Chemical doping methods have been widely used for 2D materials to induce a charge exchange transfer; however, they are subjected to surface contamination which can be detrimental for high quality semiconductor device processing. In this work, the authors reveal the effects of chemicals‐free doping in which annealing induces a p‐doping effect by physisorption and substitution of oxygen atoms while electron beam irradiation selectively n‐dopes MoTe2, based on the results obtained by electrical characterization and Kelvin probe force microscopy. The annealing increases work‐function of MoTe2 which undergoes oxidation as observed in the reduction of surface potential and the transition of transfer curves toward the p‐type behavior. Electrical measurements and a significant reduction in surface potential after electron beam irradiation indicate the generation of trapped charges which is responsible for the n‐doping effect. Subsequently, the authors fabricate a CMOS inverter consisting of distinctively p‐ and n‐doped areas of MoTe2.

Hydrogen permeability of non-stoichiometric tungsten oxides

This paper presents results from an investigation of the permeation rate of gaseous hydrogen through a double-layer membrane by the classic gas accumulation method at 400 °C. Dense 8-micrometer thick tungsten films were grown on highly permeable 40 mm diameter Eurofer substrates by the combined magnetron sputtering and high energy ion bombardment method. By in-situ exposure of the tungsten side to pure oxygen at 0.9 bar for 2 hours, a noticeable decrease in permeation rates at 400°C was achieved, expressed as the permeation rate reduction factor, which ranged from 3.8 to 38. Oxide characterisation followed after permeation rate tests. Focused ion beam cross-section after the oxidation/permeation rate cycle revealed an oxide layer thickness between 80 and 100 nm. X-ray diffraction and Raman analyses revealed a mixture of many non-stoichiometric oxide types after the oxidation/permeation rate cycles. Their corresponding hydrogen permeability at 400°C in the range from 8.1 × 10−18 – 5.7 × 10−17 mole H2/s/m/Pa0.5 was calculated from measured data.

ИСПОЛЬЗОВАНИЕ УРАВНЕНИЯ ШРЁДИНГЕРА ДЛЯ ИССЛЕДОВАНИЯ ЯВЛЕНИЙ, ПРОТЕКАЮЩИХ В ПЛАЗМОГЕНЕРАТОРЕ ТЛЕЮЩЕГО РАЗРЯДА

The work purpose is development of the theory ensuring creation of an efficient system of fast process control in the plasma generator of a glow discharge and contributing to the development of new techniques and equipment for their realization under conditions of controllable automated tool production. &#x0D; There are used regulations of quantum mechanics lying in that any system can be described by setting in a general case a complex wave function of the kind of . A possibility to find out a charged particle at the time t in some point of the near-cathode area of the closed volume of the plasma generator with the radius-vector was defined by probability density which is presented by a module square of the wave function of .&#x0D; In the course of the investigation carried out there are obtained the following results. The formation of charged particle flows in the plasma generator of a glow discharge has a probabilistic character. The Schroedinger equation use to obtain analytical dependences describing the processes of charged particle flows formation in the plasma generator of a glow charge is the most corresponding as it allows defining a value of their energy depending on the gas technological environment used. The rate change of gas technological environment pumping allows forming a corresponding volume of ions having specified energy and frequency, in the flow taking into account their mass and energy according to the adopted exponential distribution of ion mass in the flow. &#x0D; In automated technological environment having changed a kind of gas technological environment and a rate of its pumping it is possible to obtain predictable results of the impact of glow discharge plasma upon a surface of products worked explaining the effect of defect generation. As a result of high-energy ion bombardment of the surface of products under processing in the plasma generator of the glow discharge there is discovered the presence of a dissipative process with the elements of self-organization. The low-energy ion presence in the flow ensures an ion current transfer which results in the change of chemical and phase structure in the surface volume of material, its modification and reduction of a crystalline structure and also in amorphism on the surface.

ИСПОЛЬЗОВАНИЕ УРАВНЕНИЯ ШРЁДИНГЕРА ДЛЯ ИССЛЕДОВАНИЯ ЯВЛЕНИЙ, ПРОТЕКАЮЩИХ В ПЛАЗМОГЕНЕРАТОРЕ ТЛЕЮЩЕГО РАЗРЯДА

The work purpose is development of the theory ensuring creation of an efficient system of fast process control in the plasma generator of a glow discharge and contributing to the development of new techniques and equipment for their realization under conditions of controllable automated tool production. &#x0D; There are used regulations of quantum mechanics lying in that any system can be described by setting in a general case a complex wave function of the kind of . A possibility to find out a charged particle at the time t in some point of the near-cathode area of the closed volume of the plasma generator with the radius-vector was defined by probability density which is presented by a module square of the wave function of .&#x0D; In the course of the investigation carried out there are obtained the following results. The formation of charged particle flows in the plasma generator of a glow discharge has a probabilistic character. The Schroedinger equation use to obtain analytical dependences describing the processes of charged particle flows formation in the plasma generator of a glow charge is the most corresponding as it allows defining a value of their energy depending on the gas technological environment used. The rate change of gas technological environment pumping allows forming a corresponding volume of ions having specified energy and frequency, in the flow taking into account their mass and energy according to the adopted exponential distribution of ion mass in the flow. &#x0D; In automated technological environment having changed a kind of gas technological environment and a rate of its pumping it is possible to obtain predictable results of the impact of glow discharge plasma upon a surface of products worked explaining the effect of defect generation. As a result of high-energy ion bombardment of the surface of products under processing in the plasma generator of the glow discharge there is discovered the presence of a dissipative process with the elements of self-organization. The low-energy ion presence in the flow ensures an ion current transfer which results in the change of chemical and phase structure in the surface volume of material, its modification and reduction of a crystalline structure and also in amorphism on the surface.

Ultrahigh capacitive energy density in ion-bombarded relaxor ferroelectric films.

Dielectric capacitors can store and release electric energy at ultrafast rates and are extensively studied for applications in electronics and electric power systems. Among various candidates, thin films based on relaxor ferroelectrics, a special kind of ferroelectric with nanometer-sized domains, have attracted special attention because of their high energy densities and efficiencies. We show that high-energy ion bombardment improves the energy storage performance of relaxor ferroelectric thin films. Intrinsic point defects created by ion bombardment reduce leakage, delay low-field polarization saturation, enhance high-field polarizability, and improve breakdown strength. We demonstrate energy storage densities as high as ~133 joules per cubic centimeter with efficiencies exceeding 75%. Deterministic control of defects by means of postsynthesis processing methods such as ion bombardment can be used to overcome the trade-off between high polarizability and breakdown strength.

Defect-enhanced energy storage

Dielectrics Dielectric capacitors are vital components of electronics and power systems. The thin-film materials of which capacitors are composed are usually optimized by changing the material composition. However, Kim et al. found that postprocessing an already effective thin-film dielectric by high-energy ion bombardment further improved the material because of the introduction of specific types of defects that ultimately improved the energy storage performance. The results suggest that postprocessing may be important for developing the next generation of capacitors. Science , this issue p. [81][1] [1]: /lookup/doi/10.1126/science.abb0631