High-voltage Devices Research Articles

Gas-Generation Mechanism of Silicone Gel in High-Temperature Thermal Decomposition for High-Voltage and High-Power Device Encapsulation

Gas-Generation Mechanism of Silicone Gel in High-Temperature Thermal Decomposition for High-Voltage and High-Power Device Encapsulation

Design of epoxy composites via molecular orbital modulation and enhanced π-πF interactions achieving synchronous improvement of electrical and mechanical performance

The stacked aromatic rings in bisphenol A epoxy resins provide good mechanical properties and thermal stability while leading to the transport of conjugated delocalized electrons, which dramatically affects the insulation properties of the material. This contradiction leads to performance bottlenecks in epoxy-based encapsulation materials, further limiting the development of high-voltage semiconductor devices. In this study, fluorophenyl-modified epoxy monomers (FPMEPs) are designed to enrich the intermolecular interactions in an aromatic system while inhibiting the charge transport process, thereby solving the contradiction between the electrical and mechanical properties. Firstly, FPMEP with high insulation properties was designed by theoretical calculations and then synthesized by highly selective click chemistry. The fluorophenyl modulates the molecular orbitals of epoxy monomers and acts as a deep trap to inhibit charge injection and transport processes. Further, the π-πF stacking between the aromatic system and fluorophenyl enhances the interaction of the matrix molecules and solves the dispersion problem of fluorinated graphene (FG) fillers. The FPMEP/FG composites thus exhibit a considerable improvement in electrical and mechanical properties (breakdown strength of 39.8 kV/mm, dielectric loss of 0.011@50 Hz, tensile strength of 68.8 MPa, and adhesive strength of 2.15 MPa), and demonstrate good water repellency and aging durability. This matrix-filler synergistic modification strategy provides new insights into the design of insulation material.

Gate mesa terminal with drain-field-plated β-Ga2O3 MOSFET with ultra-high power figure of merit

In this article, a novel gate mesa terminal (GMT) device structure incorporating a drain field plate is proposed. This design features mesa terminals with varying bevel angles positioned atop the gate. The objective is to enhance the breakdown voltage (Vbr) and reduce the on-resistance (Ron) of the lateral β-Ga2O3 metal-oxide-semiconductor field-effect transistor (MOSFET). Through the implementation of the GMT structure, the peak electric field within the β-Ga2O3 MOSFET is redirected towards the passivation layer. This effectively mitigates the electric field in the epitaxial layer, thereby increasing Vbr. The optimal values for Vbr, specific on-resistance (Ron,sp) and maximum transconductance (gm) across various GMT structures are 4827 V, 9.9 mΩ·cm2 and 15.32 mS/mm, respectively. These metrics represent a 2.63-fold, 0.88-fold, and 1.25-fold improvement compared to the non-GMT structure. Additionally, when the doping concentration of epitaxial layer is 1 × 1016 cm−3, the GMT achieves an enhanced threshold voltage of +0.26 V. By simulating different bevel angles, field plate parameters, epitaxial layer doping concentrations, and mesa thicknesses, an optimal power figure of merit (PFOM) of 1.914 GW cm−2 is attained. This innovative design introduces a fresh concept for the development of the next generation of high voltage and high-power devices rated above 4 KV.

Study on the Single-Event Burnout Effect Mechanism of SiC MOSFETs Induced by Heavy Ions

As a prominent focus in high-voltage power devices, SiC MOSFETs have broad application prospects in the aerospace field. Due to the unique characteristics of the space radiation environment, the reliability of SiC MOSFETs concerning single-event effects (SEEs) has garnered widespread attention. In this study, we employed accelerator-heavy ion irradiation experiments to study the degradation characteristics for SEEs of 1.2 kV SiC MOSFETs under different bias voltages and temperature conditions. The experimental results indicate that when the drain-source voltage (VDS) exceeds 300 V, the device leakage current increases sharply, and even single-event burnout (SEB) occurs. Furthermore, a negative gate bias (VGS) can make SEB more likely via gate damage and Poole–Frenkel emission (PF), reducing the VDS threshold of the device. The radiation degradation behavior of SiC MOSFETs at different temperatures was compared and analyzed, showing that although high temperatures can increase the safe operating voltage of VDS, they can also cause more severe latent gate damage. Through an in-depth analysis of the experimental data, the physical mechanism by which heavy ion irradiation causes gate leakage in SiC MOSFETs was explored. These research findings provide an essential basis for the reliable design of SiC MOSFETs in aerospace applications.

(Invited) Consideration on Gate Stack Formation Processes of Ultrawide Bandgap Ga2O3 with SiO2 Dielectric Layer

MOSFETs on β-Ga2O3 are expected to be a high-efficient and cost-effective alternative option of high-voltage power devices. Taking account of the reliability and the large conduction-band offset against β-Ga2O3, it would be reasonable to employ SiO2 as the gate dieletric. In this study we investigated the effects of post-deposition annealing (PDA) on SiO2/β-Ga2O3 MOS gate stacks, in terms of the MOS electrical characteristics and the band alignment.β-Ga2O3 (001) wafers with ~2×1016 cm-3 n-type doped epitaxial layers were cleaned in diluted HF solution, and SiO2 films were deposited by electron-beam (EB) evaporation of Si in O2 ambient of ~1×10-2 Pa, followed by PDA at various temperatures from 600 to 1000℃ in either O2 or N2 ambient. Au was evaporated as gate electrode to form MOS capacitors. X-ray photoelectron spectroscopy (XPS) was conducted on the stacks with ~3nm-thick SiO2 for the evaluation of band alignment. Ultraviolet photoelectron spectroscopy (UPS) was also employed to determine the band diagram of β-Ga2O3 (001).Nearly-ideal capacitance-voltage characteristics were obtained for the MOS capacitor fabricated with O2-PDA at 1000℃. The interface state density (Dit) determined by conductance method decreased down to ~1010 cm-3 at the energy level of EC−0.2 eV by PDA at higher temperature. The hysteresis width (ΔVhys) of C-V curves was smaller for the samples annealed at higher temperatures. The flatband voltage (VFB) shift after O2-PDA resulted in VFB close to the ideal value estimated from the physical properties of Au and Ga2O3, suggesting that fixed charge density at the interface would be minimized. However, PDA in N2 at 1000℃ resulted in a negative shift of VFB, which indicates the formation of positive fixed charges in the stack. The beneficial influences of O2-PDA on those characteristics suggest that an oxygen deficiency introduced near the interface is one of the origins of interface defect states. It is noteworthy that Ga3d XPS on the surface of Ga2O3 substrate always shows a tailing in lower binding energy side, which is indicating oxygen deficiency on the surface. The intensity of this lower-binding-energy component reduced significantly when a bare-Ga2O3 substate was annealed in O2, however, it did not decrease efficiently even after O2-PDA when the surface was covered with SiO2. This is probably due to the oxygen rearrangement at SiO2/Ga2O3 interface determined by the difference of material properties of those oxides. This fact suggests that the Ga2O3 surface easily forms oxygen vacancies when it is covered with SiO2. This would be the reason why the formation of interface defect states is not suppressed without O2-PDA.Next the band diagram of β-Ga2O3 (001) substrate was investigated by UPS analysis where the energy level of valence band edge referring to the vacuum level was evaluted from the energy difference between minimum (cut-off) and maximum edges of the obtained kinetic energy spectra of photoelectrons. As a result we found the valence band edge of of β-Ga2O3 (001) was ~8.2 eV below the vacuum level, where the influences of O2 annealing at 1000℃ on the valence band edge energy level was limited to the shift within ~0.1eV. This would tell us the valence band offset between SiO2 and Ga2O3 should be around ~1.1eV, and the conduction band offset between them is to be around 2.8-2.9eV, by taking account of the well-reported SiO2 band diagram and assuming the bandgap of β-Ga2O3 as 4.7eV. On the other hand, the valence band offset estimated from the deconvolution of the XPS valence band spectrum for a ~3nm-thick SiO2/β-Ga2O3 stack from the energy edge difference between the deconvoluted spectra corresponding to SiO2 and Ga2O3, was a few hundreds of mV smaller than the above expected value (~1.1eV). This discrepancy is indicating the formation of an interface dipole layer between SiO2 and Ga2O3 with a pair of nagative and positive charges aligned at the interface to cause a shift in the band alignment. The magnitude of such dipole was indicated to be more significant (~0.5eV) for the stack after PDA at 1000℃, whereas it was less (0.2~0.3eV) after PDA at 600℃.In conclusion, we demonstrated that SiO2/β-Ga2O3 (001) MOS capacitors showed nearly-ideal electrical characteristics with significantly reduced interface defect density and small fixed charge density by applying O2-PDA. The band alignment of SiO2/β-Ga2O3 (001) MOS stack was clarified by photoelectron spectroscopy to confirm a very large conduction band offset of the stack, but an influence of the formation of interface dipole layer between SiO2 and Ga2O3 on the band alighment was also indicated.

(Invited) Advanced Electronic Characterization of Wide Band Gap Semiconductor Defects at the Nanoscale

Wide bandgap materials such as gallium nitride (GaN) and gallium oxide (Ga2O3) are currently under development for realizing next-generation high power electronic devices beyond silicon. Vertical structures produced through homoepitaxial growth are preferred for scaling high-voltage devices, which places strict demands on the quality of bulk substrates. In particular, extended defects can propagate during epitaxial growth into the active areas of devices. Therefore, there is a need for identifying defects and determining their electronic properties at relevant nano- to micro- scale dimensions in order to disentangle their combined effects on macroscopic devices. Here, we use a combination of laser-based photoemission electron microscopy (PEEM) and electrical atomic force microscopy (AFM) methodologies to investigate the local electronic properties of surface defects in epitaxially grown GaN and β-Ga2O3. PEEM is a non-scanning electron microscopy technique where photoelectrons emitted by a surface illuminated by deep-ultraviolet light are imaged with nanometer-scale spatial resolution. The emitted photoelectrons are sensitive to the local electronic structure, making PEEM a powerful tool for evaluating electronic changes at length scales relevant for devices, and provides valuable information for identifying “killer” defects which must be minimized during device growth and processing.The difficulty in producing large, low dislocation density bulk GaN substrates has led to longstanding issues with leakage current in diodes and transistor devices. We identify surface defects with different electronic properties in GaN epitaxy on different substrates using PEEM. We observe star-shaped defects on strain-patterned GaN substrates and elongated dark patches on growth ridges on ammonothermally grown GaN substrates. In both cases, the observed electronic changes in PEEM correlate directly with local electrical AFM measurements, revealing that local changes in the electronic structure at these defects results in altered electrical conduction.In contrast, the development of large bulk Ga2O3 substrates has been more successful, yet the identification and influence of various defects on device performance is still largely unknown at this point. The topography of β-Ga2O3 epitaxy varies widely between growth methods and substrate orientations. For example, β-Ga2O3 by hydride vapor physical epitaxy lacks fine structure, yet has surface defects that regularly appear in parallel orientations. In β-Ga2O3 grown on different substrate orientations, we observe variations in the surface electronic properties using PEEM. For certain substrate orientations and growths, we find nanoscale variations in doping, while other orientations display micron-scale electronic inhomogeneity and defects. Our results demonstrate that laser-based PEEM can be a powerful tool for detecting electrically active defects, as well as evaluating the nanoscale electronic homogeneity of wide bandgap semiconductors.

Research on single event effects and hardening design of LDMOS transistors

In this paper, an N-type Lateral Diffused Metal Oxide Semiconductor (LDMOS) device was designed using a heavily doped P+ well and drain N-type buffer layer structure in the BCD process. The hardened mechanism of heavily doped P+ well and drain N-type buffer layer structures was simulated and analyzed using a TCAD device simulator. To verify the anti-SEE performance of the LDMOS, the irradiation test was conducted using Ta ion (LET = 79.2 MeV·cm−2 mg−1). The results show that increasing P+ well doping concentration and using buffer layer structure can increase the single event burnout (SEB) voltage of high-voltage LDMOS devices. SEB did not occur within the full operation voltage range.

To the problem of the shielding systems efficiency in constructions of extra-high voltage electrical apparatus

In the article, the authors proposed a method for estimating the electric load parameters to calculate the distribution of the electric field strength of the solid insulating structure of gas-filled high-voltage devices with axial symmetry. This structure consists of a support and insulating busbar filled with SF6 gas as an internal insulating medium. This technique allows to evaluate the parameters of the electrical load (voltage and field strength) depen-ding on the design features of the device and the shielding system used to equalize the electric field. The proposed methodology allows to evaluate the effectiveness of the influence of design parameters of the protection system for gas-filled high-voltage equipment (instrument transformers, arresters, surge arresters, etc.) when designing and improving individual design solutions. The calculation results are in good agreement with the data of experimental studies and statistical information obtained as a result of monitoring the operation of insulating structures, taking into account actual operating conditions and the influence of external factors. The implementation of this technique allows us to take into account the influence of external factors and operational characteristics inherent in instrument transformers and surge suppressors. In the proposed methodology, as an example, we consider a supporting insulating coating that is in operation under the most unfavorable conditions, such as external pollution, moisture and their combination, overvoltage of various origins, etc. The theoretical conclusions are confirmed by the results of calculations using the example of the support-insulating cover of the surge suppressor of the OПН-500 series. A more accurate determination of the effectiveness of the proposed methodology for predicting the field strength distribution parameters under the influence of a shielding system can be achieved by conducting an additional series of calculations and experimental tests of specific insulating structures. Thus, it was concluded that the obtained results can be used to evaluate the external insulation characteristics of both surge suppressors and gas-filled instrument transformers, as well as similar high-voltage equipment of switchgears and transformer substations in conditions of ultra- and transformer substations ultra-high voltages

Tunability of the electronic structure of GaN third generation semiconductor for enhanced band gap: The influence of B concentration

To meet the demand of the future high energy, high voltage, high frequency, high temperature and high power electronic devices, the improvement of wide band gap is very significance for the applications of the third generation semiconductor material. To improve the band gap of GaN, the influence of B-doped concentration on the electronic and optical properties of GaN semiconductor is studied by the first-principles method. Four B-doped concentrations (3.125 at%, 6.25 at%, 12.5 at% and 25 at %) are investigated. The calculated results show that these B-doped GaN are thermodynamic stability because of the negative doped formation energy. In particular, the thermodynamic stability of the B-doped GaN becomes better with increasing B concentration. Importantly, the band gap follows the order of 25 at% B-doping > 12.5 at% B-doping > 6.25 at% B-doping > 3.125 at% B-doping > GaN. The band gap of 25 at% B-doped GaN increases about 70 % compared to GaN. Essentially, the B-doping induces the conduction band to move from the EF to the high energy region, which enhances the difficult of electronic transfer between the valence band and conduction band near the Fermi level. The semiconductor properties of the B-doped GaN are demonstrated by the dielectric functional. In addition, the B-doping is beneficial to improve the storage optical properties of GaN. Therefore, we believe that the B-doping can improve band gap and optical properties of GaN, which is potentially used in the high power, high voltage, low loss devices and deep ultraviolet optoelectronics.

Analysis of the features of the shielding system of polymer insulation structures of high voltage electrical equipment

In the article, the authors analysed the existing shielding systems of insulating structures of high-voltage devices together with electrodes under high potential. At the same time, the possibilities of using toroidal screens of various designs and the conditions of their installation in gas-filled equipment structures (gas-filled current and voltage measuring transformers, arresters, etc.) using polymer insulating materials are considered. Based on the analysis of literary sources, the most effective method of estimating the electric load parameters for determining the electric field strength distribution along the continuous insulating structure of gas-filled high-voltage devices with axial symmetry is proposed. This design is a support-insulating shell filled with SF6 as an internal insulating medium. Methodical materials are recommended that allow you to estimate the electrical load parameters (voltage and field strength) depending on the design features of the device and the shielding system used to level the electric field. Based on them, it is possible to evaluate the effectiveness of the calculation coefficients of the shielding system of gas-filled high-voltage equipment in the design process and during the improvement of individual design solutions. The results of the analytical evaluation by such methods are in good agreement with the data of experimental studies and statistical information obtained as a result of monitoring the work of insulating structures, taking into account real operating conditions and the influence of external factors. The introduction of the obtained materials allows you to take into account the influence of external factors and operational characteristics inherent in measuring transformers and overvoltage limiters. To explain the results of the analysis of methodical materials carried out in the article, as an example, the results of calculations of the support-insulation shell of the gas-filled current transformer of the TOG series, which was the most affected during operation, are given. in adverse conditions, given under such conditions as external pollution, humidity and their combination, as well as under conditions of overvoltage of various origins, etc. On the basis of the presented materials, it is possible to more accurately determine the effectiveness of various screenings. system, as well as how to predict the field strength distribution parameters under the influence of the shielding system, taking into account its design features. In addition, on the basis of the conclusions formed in the work, it is possible to plan and conduct an additional series of calculations and experimental tests taking into account the features of specific structures. Thus, the obtained results can be used to evaluate the external insulation parameters of both gas-filled measuring transformers and similar high-voltage equipment of distribution devices and transformer substations.

Over 600 V Lateral AlN-on-AlN Schottky Barrier Diodes with Ultra-Low Ideality Factor

This letter reports the demonstration of lateral AlN Schottky barrier diodes (SBDs) on single-crystal AlN substrates by metalorganic CVD (MOCVD) with an ultra-low ideality factor (η) of 1.65, a high Schottky barrier height of 1.94 eV, a breakdown voltage (BV) of 640 V, and a record high normalized BV by the anode-to-cathode distance. The device current was dominated by thermionic emission, while most previously reported AlN SBDs suffered from defect-induced current with higher η (>4). This work represents a significant step towards high-performance ultra-wide bandgap AlN-based high-voltage and high-power devices.

Dielectric relaxation spectroscopy of hybrid insulating nanofluids in time, distribution, and frequency domain

Improving the dielectric properties of insulating liquids belongs to the modern motivation to optimize the operation of high-voltage devices. Hybrid nanofluids can provide the mentioned improvement, and thus, it is necessary to reveal their hidden potential. This study investigates hybrid nanofluids with different concentrations of magnetite and fullerene nanoparticles, a separate fullerene and magnetic nanofluid, and a base carrier fluid based on gas-to-liquid technology. The investigated samples are subjected to dielectric relaxation spectroscopy analysis at three applied electric field intensities in the time, distribution, and frequency domain. The lack of information about the studied parameters of the mentioned nanofluids is another reason for our experimental measurements. A significant dispersion of the charging current characteristics of nanofluids with magnetic nanoparticles is observed. At lower electric field intensities, the increasing fullerene concentration of the hybrid nanofluids reduces the charging currents up to a charging time of 200 s. Magnetic nanofluid shows the highest values of conductivity currents. Experiments show that the suspension of fullerene in the base oil causes a higher charging current and a more pronounced relaxation response than pure base oil. Significant relaxation information in the low-frequency band is detected from the distribution spectra. At higher electric field intensities in the low-frequency spectrum, the relaxation peaks decrease when the concentration of fullerene in hybrid nanofluids increases. The distribution area shows the effect of higher polarizability of magnetite nanoparticles. Compared to lower electric field intensities, at the value of 333.3 kV/m, several polarization processes are captured in the entire frequency spectrum. The frequency-dependent complex permittivity confirms the findings from the time and distribution domains. Comparing the distribution domain with the frequency domain shows higher sensitivity and accuracy in capturing relaxation processes in the distribution domain.

How Are High-Voltage Devices Used for Primary Prevention in Very Elderly Patients?

How Are High-Voltage Devices Used for Primary Prevention in Very Elderly Patients?

Impact of High-Voltage Device Implantation in Elderly Japanese Patients With Heart Failure as Primary Prevention - Post Hoc Analysis of HINODE.

Despite an increased incidence of chronic heart failure (HF) and sudden cardiac death (SCD), the use of implantable cardioverter-defibrillators (ICDs) and cardiac resynchronization therapy (CRT) is much lower in Japan than in Western countries. The HF Indication and SCD Prevention Trial Japan (HINODE) prospectively assessed the mortality rate, appropriately treated ventricular arrhythmias (VA), and HF in Japanese patients with a higher risk of HF.Methods and Results: HINODE consisted of ICD, CRT-defibrillator (CRT-D), pacing, and non-device treatment cohorts. This subanalysis evaluated the impact of the implantation of high-voltage devices (HVD; ICD and CRT-D) in 171 Japanese patients. We compared all-cause mortality, VA, and HF events between elderly (age >70 years at study enrollment) and non-elderly HVD recipients. The estimated survival rate through 24 months in the HVD cohort was 85.8% (97.5% lower control limit 77.6%). The risk of all-cause mortality was increased for the elderly vs. non-elderly (hazard ratio [HR] 2.82; 95% confidence interval [CI] 1.01-7.91; P=0.039), but did not differ after excluding ICD patients with CRT-D indication (HR 2.32; 95% CI 0.79-6.78; P=0.11). There were no differences in VA and HF event-free rates between elderly and non-elderly HVD recipients (P=0.73 and P=0.55, respectively). Although elderly patients may have a higher risk of mortality in general, the benefit of HVD therapy in this group is comparable to that in non-elderly patients.

High-voltage (> 3 V) energy storage device based on sputter-grown TiCrN microelectrodes towards miniaturized applications

In this work, we report sputter-grown micro-patterns of titanium chromium-based bimetallic nitride (TiCrN) over Si/SiO2 substrate. The highly stable TiCrN-micro pattern is tested electrochemically and used to construct an efficient microsupercapacitor (MSC) device. To achieve a stable and high-voltage window, a non-aqueous gel polymer electrolyte (GPE) of TEABF4/EC/PC/PVDF is optimized. At room temperature, the GPE exhibits high ionic conductivity of ~10.58 mS cm−1 with exceptional mechanical stability. A symmetric supercapacitor based on TiCrN sandwich structure (TiCrN-SS) is fabricated with TEABF4 GPE for practical application. The TiCrN-SS device works on a high voltage of 3.1 V and exhibits good electrochemical properties. The device shows a high energy density of 1.9 μWh cm−2 (5.9 Wh kg−1) at a power density of 109 μW cm−2 (0.34 kW kg−1). To utilize the excellent performance of TiCrN-SS as a miniaturized power source, an on-chip MSC is subsequently fabricated by patterning planar interdigitated TiCrN-microelectrodes. The constructed on-chip TiCrN microsupercapacitor (TiCrN-MSC) works on a wide voltage window of 0–3.1 V while maintaining an optimum areal capacitance of ~500 μF cm−2 at 0.07 mA cm−2 current density. The device exhibits an areal energy density of ~0.7 μWh cm−2 with an optimum 169.02 μW cm−2 power density. This remarkable electrochemical performance and exceptionally wide voltage window of TiCrN-based MSC makes it a potential candidate for direct use as a miniaturized power source in microelectronic devices.

Electrode structural effects on the mechanism of high-voltage pulse rock breaking

In the oil drilling process, drilling costs account for more than 50% of total E&P costs. High-voltage electric pulse rock breaking is an economical and effective rock-breaking method that has received widespread attention. At present, there is not much research on the influence of the shape of the electrode tip on high-voltage pulse rock breaking. This paper establishes a system of equations that control the electric breakdown field based on the changes in the electric field inside the rock. Then, using this model, we conducted simulation and laboratory experiments to understand how rocks break under different conditions, such as load voltages, electrode spacing, and electrode tip shapes. The results show that the volume of broken rock is directly related to the loading voltage. The best loading voltage range is between 200 and 220 kV. Increasing the spacing between electrodes helps break more rock, but if the electrode spacing is too large, it's hard to make a hole in the rock, and the rock won't break. An electrode spacing of around 35 mm is the best. The shape of different electrode tips directly affects the high-voltage pulse breaking effect. Hemispherical electrode tips are less favorable for rock breaking, while oval electrode tips are the best. The laboratory experiments and simulations give the same conclusions and verify the applicability and correctness of our model. This study aims to help design high-voltage electric pulse devices.

Vertical diamond Schottky barrier diodes with curved field plates

Diamond Schottky barrier diodes (SBDs) could theoretically operate at high voltage, high temperature, and high frequency and be potentially used in power electronics. However, the device breaks down prematurely and cannot operate stably at high voltages due to the edge electric field crowding. In this work, a vertical diamond SBD with a curved field plate (CFP) was prepared using a chemical reflow method, inductively coupled plasma etching, and electron-beam evaporation. This structure alleviates the electric field crowding at the edge of the Schottky electrode and results in a breakdown voltage and current density of 380 V and over 3000 A/cm2, respectively. After repetitive measurements, we found that the device can repeatedly breakdown at around 380 V. These results indicate that CFP structure diamond SBDs have great application in high-voltage and high-power electronic devices.

Impact of Immunosuppressive Therapy on Lead Dislodgement After Cardiac Implantable Electronic Device Implantation.

Lead dislodgement is a severe complication in cardiac implantable electronic device (CIED) implantation. Inflammation after CIED implantation results in the development of adhesions between lead and tissues, resulting in the lead becoming fixed in the body. In patients with immunosuppressive therapy, however, adhesion is inhibited by anti-inflammatory effects. However, the association between lead dislodgement and immunosuppressive therapy has not been clarified. The purpose of this study was to investigate the association between lead dislodgement and immunosuppressive therapy. We hypothesized that lead dislodgement more frequently occur in patients with immunosuppressive therapy than those without. In total, 651 consecutive patients who underwent CIED implantation or lead addition (age, 76 ± 11 years; and males, 374 [58%], high voltage device, 121 [19%], lead addition 23 [4%]) were retrospectively enrolled. Immunosuppressive therapy was with regular steroids or immunosuppressants. Lead placement was guided by fluoroscopy, and active fixation leads were used. Restraint of the upper limb by chest tape was performed for 1 week after the procedure. Lead dislodgement was defined as a change in lead position and/or lead failure requiring reoperation. Twenty (3.1%) patients received immunosuppressive therapy. Among these, 15 (2.3%) patients regularly took steroids and 8 (1.2%) took immunosuppressants. Lead dislodgement occurred in 10 (1.5%) patients. Lead dislodgement was more frequent in patients with immunosuppressive therapy than in those without (3 [15%] vs. 7 [1%], p = 0.003). In patients with CIED implantation or lead addition, lead dislodgement is more frequent in patients with immunosuppressive therapy than in those without.

High-Voltage ESD Protection Devices With High Robustness of 13 kV and Strong Radiation Tolerance up to 200 krad(Si)

High-Voltage ESD Protection Devices With High Robustness of 13 kV and Strong Radiation Tolerance up to 200 krad(Si)

Modification of Insulating Properties of Surfaces of Dielectric High-Voltage Devices Using Plasma

Modification of Insulating Properties of Surfaces of Dielectric High-Voltage Devices Using Plasma