Breakdown Voltage Characteristics Research Articles

Improved reverse-bias breakdown behavior in fully-vertical GaN-on-Si Schottky barrier diodes with a thin AlN layer within the GaN drift layer

In this study, we investigated the effect of inserting a 1 nm thick AlN thin-film layer in the drift layer of a GaN-on-Si Schottky barrier diode to improve the reverse-bias breakdown voltage. The breakdown voltage was significantly improved from 258 V (without an AlN layer) to 338 V (with an AlN layer placed at the bottom of the drift layer), indicating that the AlN thin layer played an important role in the breakdown voltage characteristics. Furthermore, x-ray diffraction measurements and stress evaluations indicate that the AlN thin-film layer inserted at the bottom of the drift layer can significantly reduce the film stress and improve the breakdown voltage of the device.

Enhancement of the Characteristics of Natural Ester in Transformer Oil Insulation using Nanofluids

Oil is utilized in large transformers for its insulation properties and cooling. Mineral oil (MO) is not recyclable and it poses environment risks as it serves as insulation in transformer. It can be avoided by using a liquid coolant that has all the key qualities of transformer oil and seems to be biodegradable. Natural ester, made from plants as a substitute for mineral oil, has several profits. More investigations were conducted to improve the insulating liquid properties after the advent of nanofluids. In this study, a new hybrid method is employed to explore the properties by mixing different volume-percentage of hybrid nanomaterials with various natural esters. Evaluation of breakdown voltage and various transformer oil characteristics and results achieved showed that the hybrid nanofluid was essential in identifying a feasible alternative for mineral oil.

Analysis of Channel length, Gate length and Gate position Optimization of III-Nitride/β-Ga2O3 Nano-HEMT for High-Power Nanoelectronics and Terahertz Applications

This research article reports the investigation of performance optimization of the field-plated and recessed gate III-Nitride nano-HEMT on β-Ga2O3 substrate. The optimization is done for channel length, gate length and suitable gate position in order to achieve a better DC and RF characteristics for high power and THz applications. The breakdown voltage and frequency characteristics of HEMTs are typically traded off. However, the proposed III-Nitride nano-HEMT grown over β-Ga2O3 substrate incorporating an optimal channel length, gate size, and suitable gate position exhibit improved breakdown voltage characteristics without sacrificing high-frequency properties. The III-nitride HEMT comprising of 250 nm channel length, 20 nm gate length, and gate position of 120 nm from source and 110 nm from drain exhibited the improved breakdown voltage characteristics and superior RF properties. The major factor contributing to this outcome is an improved lattice compatibility of substrate material with the buffer. This study intends to advance a thorough understanding of a breakthrough III-Nitride HEMT grown on β-Ga2O3 substrate, thereby facilitating further research in this state-of-the-art technology.

Experimental Platform for Measuring Electrical Discharges in Long Air Gaps With Floating Objects and Its Applications Under Lightning Impulse

Long air gaps containing floating objects are common gaps in power transmission and substation projects. Investigating the discharge mechanism of gaps helps improve the power grid operational reliability. This article presents an experimental platform for measuring the electrical discharges in long air gaps with floating objects, which can measure the applied voltage and the discharge current, and capture the images of the discharge process. By analyzing these measured data, the breakdown voltage characteristics of the gap can be explained. In a long air gap with a floating conductive object under lightning impulse, as the floating object moves from the high voltage (HV) electrode to the ground potential electrode, the breakdown voltage first decreases and then increases, producing a minimum breakdown voltage area (MBVA). In this article, the experimental platform was used to explain the formation of MBVA as an application example. The results show that the formation of MBVA is related to the timing relationship between the breakdown of sub-gap 1 and the discharge in sub-gap 2 entering the final jump. The minimum breakdown voltage occurs at the shortest sub-gap 1 ensuring that the discharge in sub-gap 2 enters the final jump just as sub-gap 1 is broken down.

Comprehensive Review of Power Electronic Converters in Electric Vehicle Applications

Emerging electric vehicle (EV) technology requires high-voltage energy storage systems, efficient electric motors, electrified power trains, and power converters. If we consider forecasts for EV demand and driving applications, this article comprehensively reviewed power converter topologies, control schemes, output power, reliability, losses, switching frequency, operations, charging systems, advantages, and disadvantages. This article is intended to help engineers and researchers forecast typical recharging/discharging durations, the lifetime of energy storage with the help of control systems and machine learning, and the performance probability of using AlGaN/GaN heterojunction-based high-electron-mobility transistors (HEMTs) in EV systems. The analysis of this extensive review paper suggests that the Vienna rectifier provides significant performance among all AC–DC rectifier converters. Moreover, the multi-device interleaved DC–DC boost converter is best suited for the DC–DC conversion stage. Among DC–AC converters, the third harmonic injected seven-level inverter is found to be one of the best in EV driving. Furthermore, the utilization of multi-level inverters can terminate the requirement of the intermediate DC–DC converter. In addition, the current status, opportunities, challenges, and applications of wireless power transfer in hybrid and all-electric vehicles were also discussed in this paper. Moreover, the adoption of wide bandgap semiconductors was considered. Because of their higher power density, breakdown voltage, and switching frequency characteristics, a light yet efficient power converter design can be achieved for EVs. Finally, the article’s intent was to provide a reference for engineers and researchers in the automobile industry for forecasting calculations.

Analysis of Operational Characteristics of AlGaN/GaN High-Electron-Mobility Transistor with Various Slant-Gate-Based Structures: A Simulation Study.

This study investigates the operational characteristics of AlGaN/GaN high-electron-mobility transistors (HEMTs) by applying a slant-gate structure and drain-side extended field-plate (FP) for improved breakdown voltage. Prior to the analysis of slant-gate-based HEMT, simulation parameters were extracted from the measured data of fabricated basic T-gate HEMTs to secure the reliability of the results. We suggest three different types of slant-gate structures that connect the basic T-gate electrode boundary to the 1st and 2nd SiN passivation layers obliquely. To consider both the breakdown voltage and frequency characteristics, the DC and RF characteristics of various slant-gate structures including the self-heating effect were analyzed by TCAD simulation. We then applied a drain-side extended FP to further increase the breakdown voltage. The maximum breakdown voltage was achieved at the FP length of 0.4 μm. Finally, we conclude that the slant-gate structures can improve breakdown voltage by up to 66% without compromising the frequency characteristics of the HEMT. When the drain-side FP is applied to a slant-gate structure, the breakdown voltage is further improved by up to 108%, but the frequency characteristics deteriorate. Therefore, AlGaN/GaN HEMTs with an optimized slant-gate-based structure can ultimately be a promising candidate for high-power and high-frequency applications.

Empirical Model Application to Analyze Reliability and Hazards in Pongamia Oil Using Breakdown Voltage Characteristics

This research investigates a tropical indigenous nonedible ester such as Pongamia oil (PO). PO and PO methyl ester (POME) were taken as test samples to develop a nonparametric model for investigations. This work implements the empirical cumulative distribution function (eCDF) to develop a PO and POME lifetime model. The lifetime model of the PO and POME acts as a decisive factor in determining the early failure regions corresponding to the bathtub model. On the other hand, the Bayesian theorem calculates the Bayesian inference. This enables one to foresee the variable as a posterior distribution to conclude their correlation in the parameter space. The developed lifetime model of PO and POME supports experimental results over hypothesis and assists one to predict the risk probability. The model predicted early failures of the PO at less than 40 kV and POME at less than 54 kV and life of POME from 41 to 54 kV and POME at 55–65 kV. The useful life of PO and POME will experience a failure rate of 45% and 25%, respectively. Furthermore, such detections aid power engineers to treat insulating fluids to overcome early aging effects and deterioration of oil–paper insulation.

Carrier Stored Trench-Gate Bipolar Transistor With Stepped Split Trench-Gate Structure

In this work, a stepped split trench-gate (SSG) insulated-gate bipolar transistor (IGBT) employing enhanced carrier storage (CS) technique is proposed. The trench gate is split into two symmetrical gates in a deep trench structure (connected to the emitter). The bottom of the deep trench is embedded into the drift region to reduce the Miller capacitance and improve the breakdown voltage (BV) characteristics simultaneously. Additional arsenic ion implantation is performed during stepped trench formation enabling high doping CS layer. The simulation results show that in comparison with conventional carrier stored trench-gate bipolar transistor (CSTBT), the gate-to-collector charge ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${Q}_{{\mathrm {GC}}}$ </tex-math></inline-formula> ) and ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$E_{\text {OFF }}$ </tex-math></inline-formula> ) of the proposed device are decreased by 51.5% and 35.6%, respectively, with a constant conduction voltage drop ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$V_{\mathrm{ON}}$ </tex-math></inline-formula> ) of 1.36 V. In addition, an optimized tradeoff between <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$V_{\mathrm{ON}}$ </tex-math></inline-formula> and BV has been achieved. The proposed device shown here can offer an attractive technical approach with compatible manufacturing process toward high-performance power electronics applications.

Breakdown voltage characteristics of combined air gaps under negative lightning impulse

Long air gaps are the main external insulation medium of overhead transmission lines. When there are floating conductors in the air gap, the gap’s configuration changes, and the combined air gaps is formed. We built an experimental platform to obtain the breakdown characteristics of a 2 m rod–plane air gap with a rod floating conductor in different positions under negative lightning impulse. The results show that as the distance between the floating conductor and the high voltage conductor changes, the breakdown voltage (BV) and timing change. Moreover, the breakdown voltage increases with the length of sub-gap 1, showing a trend of first increasing, then decreasing, and then increasing, which is different from the trend under positive lightning impulse. The reason for this phenomenon is inferred from the analysis to be related to the polarity effect.

P‐11: Effects of Ar Dilution on N2O/SiH4 PECVD for the Growth of Silicon Oxide Thin Films with Improved Breakdown Voltage Characteristics

In order to obtain a robust gate dielectric, the nitrogen atom incorporation in the silicon oxide thin film has been investigated in much prior study in recent years. Silicon oxide thin film deposition is mainly performed using SiH4‐N2O plasma by the Plasma enhanced chemical vapor deposition (PECVD) system. Reducing the N2O/SiH4 gas flow ratio increases the nitrogen content in the film. However, the film uniformity dramatically deteriorates as the N2O/SiH4 ratio is decreased and this issue makes the low N2O/SiH4 ratio condition a challenging area for the process condition. In this study, to overcome this problem Argon (Ar) addition was employed to the low N2O/SiH4 ratio plasma and we found that Ar not only allows the thin film to be uniformly deposited by increasing the plasma density due to the penning effect, but also increases Si‐N bond especially under the ratio of 10:1 condition. Even though the silicon oxide thin film was deposited with low N2O/SiH4 gas flow rate, the film uniformity and breakdown voltage characteristics dramatically improved by Ar dilution. In addition, LTPS p‐channel TFT was fabricated by utilizing the improved silicon oxide thin film as a gate dielectric layer and it showed excellent electrical characteristics. This work would be one of the most practical solutions for robust gate dielectric deposition.

ANALISIS KARAKTERISTIK DIELEKTRIK BERBAGAI MINYAK NABATI SEBAGAI ALTERNATIF ISOLASI CAIR UNTUK TRANSFORMATOR TENAGA

This article discusses the analysis of the dielectric characteristics of various vegetable oils as an alternative to liquid insulation for power transformers. Vegetable oil in this study focused on three kinds of vegetable oil, namely kemiri sunan oil, castor oil, and palm oil. This study reviews the dialectical characteristics of the three oils with respect to temperature changes. This vegetable oil will be compared with transformer oil, namely Shell Diala B, to determine the feasibility of vegetable insulating oil. This article uses literature study and data collection methods, using the basic theory of transformers, namely when alternating electric current flows around an iron core, the iron core will turn into a magnet. The results of this study indicate that these three vegetable oils have the same breakdown voltage characteristics to temperature changes, namely at a temperature voltage of 30°C. Furthermore, these three types of oil are still below the standard SPLN 49-1: 1982 which is 30 kV and still do not have the feasibility of transformer insulation oil. When palm oil is increased to 70°C, the breakdown voltage increases quite drastically, which is 48.58 kV. This has met the standard when compared to Sell diala B oil which when the temperature changes 70°C the breakdown voltage is 47.09 kV.

AlInN/GaN HEMT on Silicon Substrate with GD-Field-Plate: Modelling and Simulation of Electric-Field and Breakdown-Voltage Characteristics

AlInN/GaN HEMT on Silicon Substrate with GD-Field-Plate: Modelling and Simulation of Electric-Field and Breakdown-Voltage Characteristics

Photoelectric Generation Coefficient of B‐Gallium Oxide during Exposure to High‐Energy Ionizing Radiation

For utilization in environments where radiation causes concern, a material's photogeneration coefficient proves essential for device designers. To extract this parameter for gallium oxide, which exhibits higher breakdown voltage characteristics compared with other commonly used semiconductor materials, making it desirable for high-power applications, Schottky diodes receive high-dose-rate radiation from an electron linear accelerator. Monitoring photogenerated charge versus dose rate reveals a photogeneration coefficient of 2.4 × 1015 pairs (cm−3-rad(Si)−1) for epitaxially grown β-phase gallium oxide.

P-type AlN based heteroepitaxial diodes with Schottky, Pin, and junction barrier Schottky character achieving significant breakdown performance

The recent achievement of p-type AlN films via Be doping was utilized to achieve novel heteroepitaxial diodes with Schottky, Pin, and junction barrier Schottky (JBS) electrical behavior. Although the heteroepitaxial structures were quasi-vertical, which is subject to many issues lowering the breakdown voltage, the Pin diode achieved a breakdown voltage of ∼25 V for a 200 nm thick unintentionally doped intrinsic layer indicating ∼50% of the theoretical breakdown voltage performance for a similar homoepitaxial GaN pin diode. JBS and Schottky diodes were implemented using the inherent and intentional stress cracking properties of AlN grown on GaN films avoiding regrowth and plasma etching, both known to be technology impediments. The density of the intentional cracks and crystalline quality of the p-AlN films was controlled via Be doping and the total metal dose supplied during the metal modulated epitaxy shutter cycle resulting in differing degrees of grown stress. Since the intentional crack density determines the surface area ratio of the Schottky diode to the Pin diode, it is a key design parameter in optimizing device performance. Furthermore, a novel current spreading layer was implemented to improve the current uniformity in these devices. The high breakdown voltage and good forward voltage characteristics of these devices shows potential to enable high-performance III-nitride high-power devices.

Optimized Device Geometry of Normally-On Field-Plate AlGaN/GaN High Electron Mobility Transistors for High Breakdown Performance Using TCAD Simulation

This study presents the optimization of the lateral device geometry and thickness of the channel and barrier layers of AlGaN/GaN high electron mobility transistors (HEMTs) for the enhancement of breakdown voltage (VBR) characteristics using a TCAD simulation. The effect of device geometry on the device performance was explored by varying the device design parameters, such as the field plate length (LFP), gate-to-drain length (LGD), gate-to-source length (LGS), gate length (LG), thickness of the Si3N4 passivation layer (Tox), thickness of the GaN channel (Tch), and AlGaN barrier (Tbarrier). The VBR was estimated from the off-state drain current versus the drain voltage (IDS–VDS) curve, and it exhibited a strong dependence on the length and thickness of the parameters. The optimum values of VBR for all the device’s geometrical parameters were evaluated, based on which, an optimized device geometry of the field-plated AlGaN/GaN HEMT structure was proposed. The optimized AlGaN/GaN HEMT structure exhibited VBR = 970 V at IGS = 0.14 A/mm, which was considerably higher than the results obtained in previous studies. The results obtained in this study could provide vital information for the selection of the device geometry for the implementation of HEMT structures.

The Effect of Temperature on the Electrical Characteristics of Nanofluids Based on Palm Oil

This study sought to apply nanotechnology to develop the electrical characteristics of palm oil. Experiments were conducted using three types of nanoparticles: zinc oxide (ZnO), titanium dioxide (TiO2), and barium titanate (BaTiO3). The nanofluid samples were prepared by mixing the nanoparticles with palm oil using various processes. In the first scenario, a combination of palm oil with nanoparticles at 0.01 vol% was created, while the next sample had 0.03 vol% of nanoparticles. The samples were then fully dispersed using a magnetic stirrer, followed by ultrasonic dispersal in order to ensure homogeneity of the nanofluid. The electrodes were set 2.5 mm apart and the test was performed six times on each test sample in compliance with the IEC 60156 standard. The voltage breakdown characteristics were recorded for each of the liquids at temperatures varying from 35 °C to 90 °C. The results showed that for the palm oil samples containing nanoparticles, the voltage breakdown was greater than for the samples containing unmodified palm oil.

Low-Temperature Electrical Performance of PureB Photodiodes Revealing Al-Metallization-Related Degradation of Dark Currents

Pure boron (PureB) deposition as the anode region of Si photodiodes creates negative fixed charge at the boron/silicon interface, which is responsible for effective suppression of electron injection from the bulk, thus ensuring low saturation/dark current densities. This mechanism is shown here to remain effective when PureB diodes, fabricated at 700 °C, are operated at cryogenic temperatures down to 100 K. Although the PureB junctions were only a few nanometers deep, they displayed the same current-voltage ( I- V) characteristics as conventional deep diffused p <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> -n junction diodes in the whole temperature range and also maintained ideality factors close to n = 1. Al-contacting was found to reveal process-related defects in the form of anomalous high current regions giving kinks in the I- V characteristics, often only visible at low temperatures. They were identified as minute Al-Si Schottky junctions with an effective barrier height of ~0.65 ± 0.05 eV. In PureB single-photon avalanche diodes (SPADs), Al-Si perimeter defects appeared but did not affect the breakdown voltage characteristics set by implicit guard rings. Low series resistance required thin B-layers that promoted tunneling. In particular, for such thin layers, avoiding Al-related degradation puts stringent requirements on wafer cleaning and window etch procedures.

Transport Parameters and Breakdown Voltage Characteristics of Gas Mixture Representing Martian Atmosphere and Its Constituents

Transport Parameters and Breakdown Voltage Characteristics of Gas Mixture Representing Martian Atmosphere and Its Constituents

A Study on the Optimization of Deep-Trench Super Junction Metal Oxide Semiconductor Field-Effect Transistor

Power metal oxide semiconductor field-effect transistor is a switching device designed to handle large power consumption; it enables fast switching, resulting in low power consumption. Power devices are used as important components that determine the operation and performance of electrically powered products such as home appliances, smartphones, and automobiles. Power devices must be able to block high voltage so that current does not flow in the off state, have no power consumption in the on state, and have a small resistance so that high current can flow. For high efficiency, power loss must be minimized and resistance must be reduced during the turn-on state. To increase the breakdown voltage, the thickness and resistivity of the N-drift region must be increased. However, owing to the trade-off relationship, as the breakdown voltage increases, the on-resistance also increases. The super junction structure was proposed to improve this trade-off relationship. In this study, a process simulation using TCAD tool was carried out. Similar to the multi-epitaxial process, the P-pillar was divided into several layers, and the value of each concentration was specified. Thus, the charge balance of the pillar regions was achieved. For the maximum breakdown voltage characteristics and minimum on-resistance characteristics of the deep-trench super junction MOSFET, an experiment was conducted to optimize the cell pitch and pillar of the super junction MOSFET using a five-deep trench.

Impact of Moisture on AC Breakdown Voltage of Crude, Refined and Transesterified Groundnut Oil-based Liquid Insulations

With the aim of analyzing the ability of vegetable oil-based liquid insulation as alternate medium under moisture-rich environment, this study presents an experimental analysis of impact on breakdown voltage characteristics vegetable oil-based insulating liquids for the moisture inclusion with oil sample. The study has been proposed to carry out with different categories of groundnut oil in crude form, refined form and transesterified form. The moisture inclusion range of 5 ppm to 25 ppm is considered based on the literature with the scope of having lower solubility level and less than 50% of water saturation level for avoiding wet transformer conditions. Experimental investigations have been done on AC breakdown voltage of three categories of groundnut oil for inclusion of proposed range of moisture. With an increased moisture level from 5 to 25 ppm, significant reduction in breakdown voltage of oil samples has been obtained with the average percentage of 53 to 67% which may be due to possible modification in the molecular component of oil with the influence of moisture's polarization characteristics. Based on the experimental observations, the empirical power equations developed based on the regression method to predict the approximate breakdown voltage at different moisture levels.