The Experts below are selected from a list of 1245 Experts worldwide ranked by ideXlab platform
Paul T. Chow - One of the best experts on this subject based on the ideXlab platform.
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Robustness of GaN vertical superjunction HEMT
2013 25th International Symposium on Power Semiconductor Devices & IC's (ISPSD), 2013Co-Authors: Zhongda Li, Paul T. ChowAbstract:We have examined the robustness of the novel enhancement-mode GaN vertical superjunction HEMT using numerical simulations, which has been designed previously and projected to have best Ron, sp of 4.2 mQ-cm2 and BV of 12.4kV, and compared it with a GaN vertical HEMT with conventional drift region. The GaN vertical superjunction HEMT with 8 μm Pillar Width shows 7X higher on-state current level and 1/5 of the Ron, sp compared with The simulated on-state breakdown voltage of the GaN vertical superjunction HEMT structure shows 4.5% drop from the off-state breakdown voltage, and is only slightly higher than the 1.7% drop of the conventional GaN vertical HEMT.
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Design and Simulation of 5–20-kV GaN Enhancement-Mode Vertical Superjunction HEMT
IEEE Transactions on Electron Devices, 2013Co-Authors: Zhongda Li, Paul T. ChowAbstract:The systematic design process using numerical simulations of the novel gallium nitride (GaN) enhancement-mode vertical superjunction high electron mobility transistor (HEMT) with breakdown voltage (BV) in the range of 5-20 kV is presented. The GaN superjunction Pillar structure in the drift region of the vertical HEMT is first optimized using a simpler GaN superjunction diode structure, and the optimum half-Pillar charge dosage is obtained to be 8×1012 cm-2, which is consistent with the value estimated from the Gauss's Law. The GaN vertical superjunction HEMT is then simulated and optimized, and the Ron,sp-BV tradeoff curves in the range of 5-20 kV are obtained by varying the epi thickness. The Ron,sp-BV tradeoff is found to improve with smaller Pillar Width as in silicon superjunction MOSFETs, and the best Ron,sp of 4.2 mΩ-cm2 with BV of 12.4 kV is projected with half-Pillar Width of 3 μm. The robustness of the superjunction HEMT is also examined using structure with half-Pillar Width of 8 μm, and compared with the GaN vertical HEMT with conventional drift layer and same dimensions. The simulated on-state BV of the GaN vertical superjunction HEMT shows a 4.5% drop from the off-state BV and is only slightly higher than the 1.7% drop of the conventional GaN vertical HEMT.
M. Takahashi - One of the best experts on this subject based on the ideXlab platform.
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Current-Induced Magnetization Switching and CPP-GMR in 30 nm $phi$ Scale Spin Valves Fabricated Using EB-Assisted CVD Hard Masks
IEEE Transactions on Magnetics, 2006Co-Authors: S. Isogami, M. Tsunoda, M. TakahashiAbstract:In this study, current-perpendicular-to-plane great magnetoresistance (CPP-GMR) spin valves with the minimum Pillar Width of 34 nm phi were successfully fabricated using EB-assisted chemical-vapor-deposition (CVD) hard masks. An area of the obtained magnetic cell is about one order smaller compared with those fabricated with normal EB or photo lithography technique. Measurement of transport properties such as current-induced magnetization switching (CIMS) and MR were demonstrated in such spin valves with various Pillar Widths. Dependence of the CPP-MR properties on the milled Pillar Width was discussed. In the case of 66 nm phi Width in particular, the MR by external magnetic field switching and CIMS were 0.4% and 0.3%, respectively. The critical switching current Ic was ~40 mA (J c~9times108 A/cm2). In the case of smaller Width, only MR by external magnetic field was observed
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Current-Induced Magnetization Switching and CPP-GMR in 30 nm$phi$Scale Spin Valves Fabricated Using EB-Assisted CVD Hard Masks
IEEE Transactions on Magnetics, 2006Co-Authors: S. Isogami, M. Tsunoda, M. TakahashiAbstract:In this study, current-perpendicular-to-plane great magnetoresistance (CPP-GMR) spin valves with the minimum Pillar Width of 34 nm phi were successfully fabricated using EB-assisted chemical-vapor-deposition (CVD) hard masks. An area of the obtained magnetic cell is about one order smaller compared with those fabricated with normal EB or photo lithography technique. Measurement of transport properties such as current-induced magnetization switching (CIMS) and MR were demonstrated in such spin valves with various Pillar Widths. Dependence of the CPP-MR properties on the milled Pillar Width was discussed. In the case of 66 nm phi Width in particular, the MR by external magnetic field switching and CIMS were 0.4% and 0.3%, respectively. The critical switching current Ic was ~40 mA (J c~9times108 A/cm2). In the case of smaller Width, only MR by external magnetic field was observed
Zhongda Li - One of the best experts on this subject based on the ideXlab platform.
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Robustness of GaN vertical superjunction HEMT
2013 25th International Symposium on Power Semiconductor Devices & IC's (ISPSD), 2013Co-Authors: Zhongda Li, Paul T. ChowAbstract:We have examined the robustness of the novel enhancement-mode GaN vertical superjunction HEMT using numerical simulations, which has been designed previously and projected to have best Ron, sp of 4.2 mQ-cm2 and BV of 12.4kV, and compared it with a GaN vertical HEMT with conventional drift region. The GaN vertical superjunction HEMT with 8 μm Pillar Width shows 7X higher on-state current level and 1/5 of the Ron, sp compared with The simulated on-state breakdown voltage of the GaN vertical superjunction HEMT structure shows 4.5% drop from the off-state breakdown voltage, and is only slightly higher than the 1.7% drop of the conventional GaN vertical HEMT.
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Design and Simulation of 5–20-kV GaN Enhancement-Mode Vertical Superjunction HEMT
IEEE Transactions on Electron Devices, 2013Co-Authors: Zhongda Li, Paul T. ChowAbstract:The systematic design process using numerical simulations of the novel gallium nitride (GaN) enhancement-mode vertical superjunction high electron mobility transistor (HEMT) with breakdown voltage (BV) in the range of 5-20 kV is presented. The GaN superjunction Pillar structure in the drift region of the vertical HEMT is first optimized using a simpler GaN superjunction diode structure, and the optimum half-Pillar charge dosage is obtained to be 8×1012 cm-2, which is consistent with the value estimated from the Gauss's Law. The GaN vertical superjunction HEMT is then simulated and optimized, and the Ron,sp-BV tradeoff curves in the range of 5-20 kV are obtained by varying the epi thickness. The Ron,sp-BV tradeoff is found to improve with smaller Pillar Width as in silicon superjunction MOSFETs, and the best Ron,sp of 4.2 mΩ-cm2 with BV of 12.4 kV is projected with half-Pillar Width of 3 μm. The robustness of the superjunction HEMT is also examined using structure with half-Pillar Width of 8 μm, and compared with the GaN vertical HEMT with conventional drift layer and same dimensions. The simulated on-state BV of the GaN vertical superjunction HEMT shows a 4.5% drop from the off-state BV and is only slightly higher than the 1.7% drop of the conventional GaN vertical HEMT.
S. Isogami - One of the best experts on this subject based on the ideXlab platform.
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Current-Induced Magnetization Switching and CPP-GMR in 30 nm $phi$ Scale Spin Valves Fabricated Using EB-Assisted CVD Hard Masks
IEEE Transactions on Magnetics, 2006Co-Authors: S. Isogami, M. Tsunoda, M. TakahashiAbstract:In this study, current-perpendicular-to-plane great magnetoresistance (CPP-GMR) spin valves with the minimum Pillar Width of 34 nm phi were successfully fabricated using EB-assisted chemical-vapor-deposition (CVD) hard masks. An area of the obtained magnetic cell is about one order smaller compared with those fabricated with normal EB or photo lithography technique. Measurement of transport properties such as current-induced magnetization switching (CIMS) and MR were demonstrated in such spin valves with various Pillar Widths. Dependence of the CPP-MR properties on the milled Pillar Width was discussed. In the case of 66 nm phi Width in particular, the MR by external magnetic field switching and CIMS were 0.4% and 0.3%, respectively. The critical switching current Ic was ~40 mA (J c~9times108 A/cm2). In the case of smaller Width, only MR by external magnetic field was observed
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Current-Induced Magnetization Switching and CPP-GMR in 30 nm$phi$Scale Spin Valves Fabricated Using EB-Assisted CVD Hard Masks
IEEE Transactions on Magnetics, 2006Co-Authors: S. Isogami, M. Tsunoda, M. TakahashiAbstract:In this study, current-perpendicular-to-plane great magnetoresistance (CPP-GMR) spin valves with the minimum Pillar Width of 34 nm phi were successfully fabricated using EB-assisted chemical-vapor-deposition (CVD) hard masks. An area of the obtained magnetic cell is about one order smaller compared with those fabricated with normal EB or photo lithography technique. Measurement of transport properties such as current-induced magnetization switching (CIMS) and MR were demonstrated in such spin valves with various Pillar Widths. Dependence of the CPP-MR properties on the milled Pillar Width was discussed. In the case of 66 nm phi Width in particular, the MR by external magnetic field switching and CIMS were 0.4% and 0.3%, respectively. The critical switching current Ic was ~40 mA (J c~9times108 A/cm2). In the case of smaller Width, only MR by external magnetic field was observed
Pengfei Shan - One of the best experts on this subject based on the ideXlab platform.
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Tightness Analysis of Underground Natural Gas and Oil Storage Caverns With Limit Pillar Widths in Bedded Rock Salt
IEEE Access, 2020Co-Authors: Nan Zhang, Yun Zhang, Pengfei ShanAbstract:To fully utilize the abandoned salt cavern resources and to increase the total amount of the fossil energy reserve of China, reconstructing some of these salt caverns for underground gas storage (UGS) or strategic petroleum reserve (SPR) would be an effective method. The salt resources in China mainly are bedded salt, which brings great challenges for the cavern construction and safety evaluation. In this paper, the investigations are presented to evaluate the tightness of the UGS and SPR salt cavern facilities, located in the bedded rock of Jintan, China. Microcosmic analysis, and permeability and porosity tests of the surrounding rock are carried out to determine their properties, which provide the basic data for the tightness assessment. A 3-D numerical model is developed based on the test results and the geological features of the target formation. The numerical simulation results show that the seepage velocity, seepage range and loss rate of leakage of the SPR salt caverns are much smaller than those of UGS salt caverns. The cavern's Pillar Width with a Pillar to diameter ratio (P/D) of 1.5 can satisfy the tightness requirement of SPR salt caverns, but it cannot meet the requirement of UGS caverns. This indicates that some existing abandoned salt caverns in Jintan which are unsuitable for UGS due to their small Pillar Width have the potential to be rebuilt for SPR. This would help to increase the storage capacity of crude oil in China. The results can also provide a reference for the implementation of similar projects in other bedded salt districts.
