The potential of replacing crosslinked polyethylene (XLPE) with an eco-friendly alternative, polypropylene (PP), as insulating material is investigated for overhead power distribution lines. Although XLPE exhibits excellent electrical and mechanical properties, the byproducts generated during crosslinking pose environmental challenges. PP is a viable alternative because of recyclability and absence of byproducts during crosslinking. This study evaluated alternating current (AC) breakdown strength, contact angle, and tracking resistance of two commercially available XLPE samples and three types of PP (PP1, PP2, PP3) with varying additive content. AC breakdown strength, analyzed using the Weibull distribution, facilitated relative comparison of insulation performance. PP2 exhibited scale parameters comparable to or exceeding those of XLPE. Contact angles exceeding 90° displayed hydrophobicity across all samples. To address pass/fail evaluation limitations, arcing images from tracking tests were analyzed using the box-counting method for fractal dimension analysis. Fractal dimensions increased with arcing extent, and complexity increased with test duration. Tracking resistance performance order was PP3, PP1, CC, PP2, OC which was attributed to enhanced heat dissipation properties of filler additives. The proposed quantitative method for comparing tracking resistance through fractal dimension analysis, explored the feasibility of using PP insulating materials in overhead power distribution lines.

Breakdown strength is an essential parameter for evaluating the electrical performance and degradation behavior of cable insulation and IEC 60243 also emphasizes its importance for detecting changes in insulation characteristics due to aging. However, the current IEC standards are mainly limited to specifying electrode configurations and test voltage conditions for breakdown tests, while the influence of insulating oil, is not clearly addressed. In this study, the breakdown strength of a 66 kV wet-type submarine cable was experimentally evaluated using insulating oils with different kinematic viscosities of 10, 100, 500, and 1,000 cSt in order to achieve reliable and reproducible breakdown measurements. The experimental results show that the measured breakdown strength decreases by up to approximately 20% depending on the oil viscosity. This indicates that the viscosity of the insulating oil has a significant influence on the measured breakdown strength during breakdown test. Therefore, it is necessary to perform breakdown strength measurements under identical test conditions, including the physical properties of the insulating oil, to ensure reliable comparison and accurate assessment of insulation performance and degradation characteristics.

Silicon carbide (SiC) power devices are attracting increasing attention for high-voltage and high-efficiency applications due to their superior material properties. However, achieving an optimal trade-off between specific on-resistance (Ron,sp) and breakdown voltage (BV) remains a key design challenge in planar MOSFET structures. In this study, twodimensional TCAD simulations were conducted to investigate the impact of varying the doping concentrations of the P-well (from 3 × 10¹⁷ to 6 × 10¹⁷ cm^-3) and JFET regions (from 1 × 10¹⁶ to 7 × 1016 cm^-3) on the electrical characteristics of 2.4 kVclass planar SiC MOSFETs. To maintain comparable BV conditions for 2.4 kV operation, two groups with P-well doping concentrations of 4.5 × 10¹⁷ cm^-3 and 5.3 × 1017 cm^-3 were analyzed and compared. When the P-well and JFET doping concentrations were 4.5 × 10¹⁷ cm^-3 and 1.5 × 10¹⁶ cm^-3, respectively, the simulated Ron,sp and BV were 1.41 mΩ·cm² and 3,150 V. In contrast, with P-well and JFET doping concentrations of 5.3 × 10¹⁷ cm^-3 and 5.0 × 10¹⁶ cm^-3, the Ron,sp was reduced to 1.31 mΩ·cm² while the BV slightly increased to 3,200 V. Based on these results, an optimized device structure was proposed, demonstrating its potential for integration into high-voltage SiC-based power systems. This study provides practical design insights and is expected to contribute to the advancement of wide bandgap semiconductor technologies for next-generation power electronics.

With the expansion of offshore wind farms, research on power cables for delivering electricity from offshore to onshore has become increasingly important. In offshore wind farms, submarine cables are introduced and secured to the platform through J-tube conduits. During this process, the cables are exposed to three distinct thermal profiles: high temperatures in the upper section, temperature fluctuations due to water level changes in the middle section, and low temperatures in the seabed region. This study investigates the impact of thermal variations on the insulation performance of submarine cables. To analyze this effect, accelerated aging tests were conducted on both insulation specimens and actual cables. Additionally, dielectric breakdown tests were performed to quantitatively assess insulation degradation. Experimental results revealed that the insulation performance of the specimens exposed to periodic temperature fluctuations due to water level changes deteriorated by up to 7.5%. Based on these findings, the vulnerable sections of submarine cables in offshore wind farms were identified. Furthermore, this study emphasizes the necessity for monitoring and protective measures to mitigate insulation degradation in these critical regions.

With the recent active development of laser-based weapons/monitoring/communication systems, there is a significant increase in the demand for improved performance of piezoelectric actuators, a key component of both deformable mirror (DM) and fast steering mirror (FSM) in the systems. The conventional polycrystalline piezoelectric ceramic actuators have limitations in improving their characteristics, so the ultrahigh strain PMN-PZT piezoelectric single crystal multilayer actuators have been developed. In this study, the basic experimental methods were developed to evaluate their stability as well as reliability. The limitations of deformation and applied voltage were confirmed through the breakdown voltage test, and the degree of stability was confirmed through the hammering test. In this study, the breakdown voltage test and the hammering test were confirmed to be effective methods to evaluate their stability as well as reliability. Through these studies, the next-generation PMN-PZT piezoelectric single-crystal multilayer actuator is expected to be applied to various piezoelectric application fields by securing reliability as well as excellent piezoelectric properties.

In this paper, the electrical properties of liquid insulating oil were analyzed by changing the ambient temperature change at 10℃ in-tervals from 0℃ to 30℃ through an insulation breakdown experiment in order to analyze the insulation performance of liquid in-sulating oil that varies according to temperature changes. As a result, it was confirmed through experiments that the lower the am-bient temperature, the higher the insulation breakdown voltage, depending on both the electrode shape and the electrode interval, and it was determined that the lower the ambient temperature, the higher the insulation performance of the liquid insulating oil.

This reports the electrical properties of single-crystal β-gallium oxide (β-Ga₂O₃) vertical Schottky barrier diodes (SBDs) with a different guard ring structure. The vertical Schottky barrier diodes (V-SBDs) were fabricated with two types guard ring structures, one is with metal deposited on the Al₂O₃ passivation layer (film guard ring: FGR) and the other is with vias formed in the Al₂O₃ passivation layer to allow the metal to contact the Ga₂O₃ surface (metal guard ring: MGR). The forward current values of FGR and MGR V-SBD are 955 mA and 666 mA at 9 V, respectively, and the specific on-resistance (Ron,sp) is 5.9 mΩ·cm² and 29 mΩ·cm². The series resistance (Rs) in the nonlinear section extracted using Cheung’s formula was 6 Ω, 4.8 Ω for FGR V-SBD, 10.7 Ω, 6.7 Ω for MGR V-SBD, respectively, and the breakdown voltage was 528 V for FGR V-SBD and 358 V for MGR V-SBD. Degradation of electrical characteristics of the MGR V-SBD can be attributed to the increased reverse leakage current caused by the guard ring structure, and it is expected that the electrical performance can be improved by preventing premature leakage current when an appropriate reverse voltage is applied to the guard ring area. On the other hand, FGR V-SBD shows overall better electrical properties than MGR V-SBD because Al₂O₃ was widely deposited on the Ga₂O₃ surface, which prevent leakage current on the Ga₂O₃ surface.

Demand and necessity for eco-friendly offshore wind farms have been increasing. Research on submarine cables is constantly being considered for a reliable and stable power transmission. This study aimed to evaluate the thermal aging characteristic of submarine cables inside the J-tube of offshore wind farms. In this study, a submarine cable was set in three sections: The first is the part exposed to the air above the sea level at high temperature. The second is the section exposed to repeated temperature fluctuation as the sea level rises and falls. The third is the part submerged at low temperature below the sea level. Aged samples were tested by using the method of electrical evaluation to obtain insulation characteristics. The experimental results show that the dielectric breakdown of the sample with temperature fluctuation was 7% lower than the sample with a constant temperature; thereby, demonstrating that the section where the temperature fluctuation occurred in the submarine cables was weaker than the other. The sections of submarine cable with temperature fluctuations are believed as a weak point during operation; therefore, this part should be monitored preferentially.

In this paper, a 1,200 V Si-based IGBT used in electric vehicles and new energy industries was designed. A field stop IGBT with a separate gate structure, which is the proposed structure, was designed to change trench depth and split gate width variables. Then, the general trench structure and electrical characteristics were compared and analyzed. As a result of conducting the trench depth experiment, it was confirmed that the breakdown voltage was the highest at 6 μm, and the on-state voltage drop was the lowest at 3.5 μm. In the separate gate width experiment, it was confirmed that the breakdown voltage decreased as the variable increased, and the on-state voltage drop increased. Therefore, it may be seen that it is preferable not to change the width of the separate gate. In addition, experiments show that there is no difference in on-state voltage drop compared to a structure in which a general field stop structure has a separate gate structure. In other words, it is determined that adding a dummy gate with a separate gate structure to the active cell will significantly improve the on-voltage drop characteristics, while confirming that the on-voltage drop does not change, and while having excellent characteristics in terms of breakdown voltage.

In this paper, the 1,700 V level SiC-based power MOSFET device widely used in electric vehicles and new energy industries was designed, that is, a single trench gate power MOSFET structure and a double trench gate power MOSFET structure were proposed to analyze electrical characteristics while changing the design and process parameters. As a result of comparing and analyzing the two structures, it can be seen that the double trench gate structure shows quite excellent characteristics according to the concentration of the drift layer, and the breakdown voltage characteristics according to the depth of the drift layer also show excellent characteristics of 200 V or more. Among them, the trench gate power MOSFET device can be applied not only to the 1,700 V class but also to a voltage range above it, and it is believed that it can replace all Si devices currently applied to electric vehicles and new energy industries.

In this paper, in order to analyze high electrical insulation and cooling performance using mineral oil, the liquid insulating oil was changed in electrode shape and distance between electrodes to compare and analyze electrical characteristics according to equal electric field, quasi-equivalent electric field, and unequal electric field. As a result, the breakdown voltages were 36,875 V and 36,875 V in the form of sphere-sphere and plate-plate electrodes with equal electric fields. The breakdown voltage was 31,475 V in the sphere-plate electrode type, which is a quasi-equilibrium field, and the breakdown voltage was 28,592 V, 27,050 V, and 22,750 V in the needle-needle, sphere-needle, and needle-plate electrode types, which are unequal fields. Through this, it is possible to know the difference in breakdown voltage according to the type of electric field. The more equal the field, the higher the breakdown voltage, and the more unequal field, the lower the breakdown voltage. The difference in insulation breakdown voltage could be seen depending on the type of electric field, the insulation breakdown voltage was higher for the more equal electric field, and the insulation breakdown voltage was lower for the more unequal electric field. Also, it was confirmed that the closer the distance between the electrodes, the higher the insulation breakdown voltage, the higher the insulation breakdown current, and the insulation breakdown voltage and the insulation breakdown current were proportional.

A breakdown voltage and breakdown electric field of the transformer insulating oil of liquid dielectric were studied in uniform electric field and non-uniform electric field and the transformer insulating oil was observed by the process reached breakdown. Insulation performance evaluation of the liquid dielectric was evaluated at the electrode spacing of 2.5 mm under the conditions of domestic and international standards (KS C IEC 60156), so a comparative review was conducted at the electrode spacing of 2.5 mm. When the electrode spacing is 2.5 mm, the average breakdown voltage is 38.5 kV for sphere-sphere electrodes, 26.6 kV for plate-plate electrodes, 22.9 kV for needle-needle electrodes, and 24.3 kV for sphere-needle electrodes. 23.7 kV for the sphere-plate electrode, and 20.7 kV for the needle-plate electrode. From these results, it can be seen that the average value of the breakdown voltage at the electrode spacing of 2.5 mm, in ascending order, is sphere-sphere, plate-plate, sphere-needle, sphere-plate, needle-needle and needle-plate. It was found that the breakdown voltage of the unequal field was lower than that of the equal field.

This paper focuses on the 1,200-V level reverse conducting-insulated gate bipolar transistor (RC-IGBT). The structure of the RC-IGBT has an n+ collector at the collector terminal. The breakdown voltage, V_th, V_ce-sat, and turn-off time, and the electrical characteristics of a field-stop IGBT (FS-IGBT) and RC-IGBT are compared and analyzed using simulations. Based on the results, the RC-IGBT obtained a turn-off time of 320.6 ㎲ and a breakdown voltage of 1,720 V, while the FS-IGBT obtained a turn-off time of 742.2 ㎲ and a breakdown voltage of 1,440 V. Therefore, RC-IGBTs have faster on/off transitions and a higher breakdown voltage, which can reduce the size of the element.

A power device is a component used as a switch or rectifier in power electronics to control high voltages. Consequently, power devices are used to improve the efficiency of electric-vehicle (EV) chargers, new energy generators, welders, and switched-mode power supplies (SMPS). Power device designs, which require high voltage, high efficiency, and high reliability, are typically based on MOSFET (metal-oxide-semiconductor field-effect transistor) and IGBT (insulated-gate bipolar transistor) structures. As a unipolar device, a MOSFET has the advantage of relatively fast switching and low tail current at turn-off compared to IGBT-based devices, which are built on bipolar structures. A superjunction structure adds a p-base region to allow a higher yield voltage due to lower RDS (on) and field dispersion than previous p-base components, significantly reducing the total gate charge. To verify the basic characteristics of the superjunction, we worked with a planar type MOSFET and Synopsys’ process simulation T-CAD tool. A basic structure of the superjunction MOSFET was produced and its changing electrical characteristics, tested under a number of environmental variables, were analyzed.

In this study, experiments and simulations were conducted for a 1,200-V-class trench Si insulated-gate bipolar transistor (IGBT) with a small cell pitch below 2.5 ㎛. Presently, as a power device, the 1,200-V-class trench Si IGBT is used for automotives including electric vehicles, hybrid electric vehicles, and industrial motors. We obtained a breakdown voltage of 1,440 V, threshold of 6 V, and state voltage drop of 1.75 V. This device is superior to conventional IGBTs featuring a planar gate. To derive its electrical characteristics, we extracted design and process parameters. The cell pitch was 0.95 ㎛ and total wafer thickness was 140 ㎛ with a resistivity of 60 Ω·cm. We will apply these results to achieve fine-pitch gate power devices suitable for electrical automotive industries.

In this letter, we propose and analyze a new asymmetric structure that can be used for next-generation power semiconductor devices. We compare and analyze the electrical characteristics of the proposed device with respect to those of symmetric devices. The proposed device has a p-emitter on the right side of the cell. The peak electric field is reduced by the shielding effect caused by the p-emitter structure. Consequently, the breakdown voltage is increased. The proposed asymmetric structure has an approximately 100% higher Baliga’s figure of merit (~94.22 MW/cm²) than the symmetric structure (~46.93 MW/cm²), and the breakdown voltage of the device increases by approximately 70%.

In this study, MOSFETs fabricated on Si-doped, MBE-grown β-Ga₂O₃ are demonstrated. A Si-doped Ga₂O₃ epitaxial layer was grown on a Fe-doped, semi-insulating 1.5 cm × 1 cm Ga₂O₃ substrate using molecular beam epitaxy (MBE). The fabricated devices are circular type MOSFETs with a gate length of 3 μm, a source-drain spacing of 20 μm, and a gate width of 523 μm. The device exhibited a good pinch-off characteristic, a high on-off drain current ratio of approximately 2.7×10⁹, and a high breakdown voltage of 1,080 V, which demonstrates the potential of Ga₂O₃ for power device applications including electric vehicles, railways, and renewable energy.

In this paper, a single N+ emitter trench gate-type insulated gate bipolar transistor (IGBT) device was studied using T-CAD, in order to achieve a low on-state voltage drop (Vce-sat) and high breakdown voltage, which would reduce power loss and device reliability. Using the simulation, the threshold voltage, breakdown voltage, and on-state voltage drop were studied as a function of the temperature, the length of time in the diffusion process (drive-in) after implant, and the trench gate depth. During the drive-in process, a 20℃ change in temperature from 1,000 to 1,160℃ over a 150 minute time frame resulted in a 1 to 4 V change in the threshold voltage and a 24 to 2.6 V change in the on-state voltage drop. As a result, a 0.5 um change in the trench depth of 3.5 to 7.5 um resulted in the breakdown voltage decreasing from 802 to 692 V.

This report constitutes the first demonstration in Korea of single-crystal lateral gallium oxide (Ga₂O₃) as a metal-oxide-semiconductor field-effect-transistor (MOSFET), with a breakdown voltage in excess of 480 V. A Si-doped channel layer was grown on a Fe-doped semi-insulating β-Ga₂O₃ (010) substrate by molecular beam epitaxy. The single-crystal substrate was grown by the edge-defined film-fed growth method and wafered to a size of 10×15 mm². Although we fabricated several types of power devices using the same process, we only report the characterization of a finger-type MOSFET with a gate length (L_g) of 2 μm and a gate-drain spacing (L_gd) of 5 μm. The MOSFET showed a favorable drain current modulation according to the gate voltage swing. A complete drain current pinch-off feature was also obtained for V_gs<-6 V, and the three-terminal off-state breakdown voltage was over 482 V in a L_gd＝5 μm device measured in Fluorinert ambient at V_gs＝-10 V. A low drain leakage current of 4.7 nA at the off-state led to a high on/off drain current ratio of approximately 5.3×10⁵. These device characteristics indicate the promising potential of Ga₂O₃-based electrical devices for next-generation high-power device applications, such as electrical autonomous vehicles, railroads, photovoltaics, renewable energy, and industry.

This paper details the design of a 1,200 V class trench gate field stop IGBT (insulated gate bipolar transistor) with a nano gate structure smaller than 1 um. Decreasing the size is important for lowering the cost and increasing the efficiency of power devices because they are high-voltage switching devices, unlike memory devices. Therefore, in this paper, we used a 2-D device and process simulations to maintain a gate width of less than 1 um, and carried out experiments to determine design and process parameters to optimize the core electrical characteristics, such as breakdown voltage and on-state voltage drop. As a result of these experiments, we obtained a wafer resistivity of 45 Ω·cm, a drift layer depth of more than 180 um, an N+ buffer resistivity of 0.08, and an N+ buffer thickness of 0.5 um, which are important for maintaining 1,200 V class IGBTs. Specially, it is more important to optimize the resistivity of the wafer than the depth of the drift layer to maintain a high breakdown voltage for these devices.

In this work, static characteristics of 4H-SiC SJ-ACCUFETs were obtained by adjusting the p-pillar region. The structure of this SJ-ACCUFET was designed by using a two-dimensional simulator. The static characteristics of SJ-ACCUFET, such as the breakdown voltages, on-resistance, and figure of merits, were obtained by varying the p-pillar doping concentration from 1×10¹⁵ cm^-3 to 5×10¹⁶ cm^-3 and the thickness from 0 μm to 9 μm. The doping concentration and the thickness of p-pillar region are closely related to the break down voltage and on-resistance and threshold voltages. Hence a silicon carbide SJ-ACCUFET structure with highly intensified breakdown voltages and low on-resistances with good figure of merits can be achieved by optimizing the p-pillar thickness and doping concentration.

In this paper, we analyzed the structural design and electrical characteristics of a 3.3 kV super junction FS IGBT as a next generation power device. The device parameters were extracted by design and process simulation. To obtain optimal breakdown voltage, we researched the breakdown characteristics. Initially, we confirmed that the breakdown voltage decreased as trench depth increased. We analyzed the breakdown voltage according to p pillar dose. As a result of the experiment, we confirmed that the breakdown voltage increased as p pillar dose increased. To obtain more than 3.3 kV, the p pillar dose was 5×10¹³ cm^-2, and the epi layer resistance was 140 Ω. We extracted design and process parameters considering the on state voltage drop.

An IGBT (insulated gate bipolar transistor) device has an excellent current-conducting capability. It has been widely employed as a switching device to use in power supplies, converters, solar inverters, and household appliances or the like, designed to handle high power. The aim with IGBT is to meet the requirements for use in ideal power semiconductor devices with a high breakdown voltage, an on-state voltage drop, a high switching speed, and high reliability for power-device applications. In general, the concentration of the drift region decreases when the breakdown voltage increases, but the on-resistance and other characteristics should be reduced to improve the breakdown voltage and on-state voltage drop characteristics by optimizing the design and structure changes. In this paper, using the T-CAD, we designed the NPT-IGBT (non punch-through IGBT) and FS-IGBT (field stop IGBT) and analyzed the electrical characteristics of those devices. Our analysis of the electrical characteristics showed that the FS-IGBT was superior to the NPT-IGBT in terms of the on-state voltage drop.

This research concerns field rings for 3.3kV planar gate power insulated-gate bipolar transistors (IGBTs). We design an optimal field ring for a 3.3kV power IGBT and analyze its electrical characteristics according to field ring parameters. Based on this background, we obtained 3.3kV high breakdown voltage and a 2.9V on state voltage drop. To obtain high breakdown voltage, we confirmed that the field ring count was 23, and we obtained optimal parameters. The gap distance between field rings 13㎛ and the field ring width was 5㎛. This design technology will be adapted to field stop IGBTs and super junction IGBTs. The thyristor device for a power conversion switch will be replaced with a super high voltage power IGBT.

This research was about shielded trench gate power MOSFET for low voltage and high speed. We used T-CAD tool and carried out process and device simulation for exracting design and process parameters. The exracted parameters was used to design shieled and conventional trench gate power MOSFET. And The electrical characteristics of shieled and conventional trench gate power MOSFET were compared and analyzed for their power device applications. As a result of analyzing electrical characteristics, the recorded breakdown voltages of both devices were around 120 V. The electric distributions of shielded and conventional trench gate power MOSFET was different. But due to the low voltage level, the breakdown voltage was almost same. And the other hand, the threshold voltage characteristics of shielded trench gate power MOSFET was superior to convention trench gate power MOSFET. In terms of on resistance characteristics, we obtained optimal oxied thickness of 3 ㎛.

Coil specimens were prepared by continuous coating on a copper wire with flexible PAI (polyamideimide) and PAI/nanosilica (5 wt%) varnish and thermally aged at 150, 200 and 250℃ for 5, 10 and 15 days, respectively. AC insulation breakdown voltage was investigated under inverter surge condition at 60 Hz and 1,000 Hz and insulation breakdown voltage decreased with increasing aging temperature and aging time at each 60 and 1,000 Hz.

This research was carried out experiments of variety IGBTs for industrial inverter and electric vehicle. The devices for this paper were planar gate IGBT, trench gate IGBT and dual gate IGBT and we designed using same design and process parameters. As a result of experiments, the electrical characteristics of planar gate IGBT were 1,459 V of breakdown voltage, 4.04 V of threshold voltage and 4.7 V of on-state voltage drop. And the electrical characteristics of trench gate IGBT were 1,473 V of breakdown voltage, 4.11 V of threshold voltage and 3.17 V of on-state voltage drop. Lastly, the electrical characteristics of dual gate IGBT were 1,467 V of breakdown voltage, 4.14 V of threshold voltage and 3.08V of on-state voltage drop. We almost knew that the trench gate IGBT was superior to dual gate IGBT in terms of breakdown voltage. On the other hand, the dual gate IGBT was better than the trench gate IGBT in terms of on state voltage drop.

This paper was researched about 1,200 V level floating island IGBT (insulated gate bipolar transistor). Presently, 1,200 V level IGBT is used in Inverter for distributed power generation. We analyzed and compared electrical charateristics of the proposed floating island IGBT and conventional IGBT. For analyzing and comparison, we used T-CAD tool and simulated the electrical charateristics of the devices. And we extracted optimal design and process parameter of the devices. As a result of experiments, we obtained 1,456 V and 1,459 V of breakdown voltages, respectively. And we obatined 4.06 V and 4.09 V of threshold voltages, respectively. On the other hand, on-state voltage drop of floating island IGBT was 3.75 V. but on-state vlotage drop of the conventional IGBT was 4.65 V. Therefore, we almost knew that the proposed floating island IGBT was superior than the conventional IGBT in terms of power dissipation.

In this paper, we analyzed the electrical characteristics of NPT planar and trench gate IGBT after designing these devices according to design and process parameter. To begin with, we have designed NPT planar gate IGBT and carried out simulation with T-CAD. Therefore, we extracted design and process parameter and obtained optimal electrical characteristics. The breakdown voltage was 724 V and The on state voltage drop was 1.746 V. The next was carried out optimal design of trench gate power IGBT. We did this research by same drift thickness and resistivity of planar gate power IGBT. As a result of experiment, we obtain 720 V breakdown voltage, 1.32 V on state voltage drop and 4.077 V threshold voltage. These results were improved performance and fabrication of trench gate power IGBT and planar gate Power IGBT.

This paper was proposed floating island power MOSFET for lowering on state resistance and the proposed device was maintained 600 V breakdown voltage. The electrical field distribution of floating island power MOSFET was dispersed to floating island between P-base and N-drift. Therefore, we designed higher doping concentration of drift region than doping concentration of planar type power MOSFET. And so we obtain the lower on resistance than on resistance of planar type power MOSFET. We needed the higher doping concentration of floating island than doping concentration of drift region and needed width and depth of floating island for formation of floating island region. We obtained the optimal parameters. The depth of floating island was 32 ㎛. The doping concentration of floating island was 5 × 1,012 ㎠. And the width of floating island was 3 ㎛. As a result of designing the floating island power MOSFET, we obtained 723 V breakdown voltage and 0.108 Ω㎠ on resistance. When we compared to planar power MOSFET, the on resistance was lowered 24.5% than its of planar power MOSFET. The proposed device will be used to electrical vehicle and renewable industry.