Zhuzhou CRRC Times Electrical Co.

Zhuzhou, China

Zhuzhou CRRC Times Electrical Co.

Zhuzhou, China
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Zhao Y.,Dynex Semiconductor | Mumby-Croft P.,Dynex Semiconductor | Jones S.,Dynex Semiconductor | Dai A.,Dynex Semiconductor | And 5 more authors.
Conference Proceedings - IEEE Applied Power Electronics Conference and Exposition - APEC | Year: 2017

Silver sinter technology is a very promising lead free interconnection method with high operating temperature, high thermal and electrical conductivity. In high power semiconductor modules the die attach material connects the die to the insulating substrate. These die attach materials need to be optimized to provide low electrical resistance and high thermal conductivity. Various silver sinter materials, such as micro or nano sized Ag paste, pressure-less or pressure assisted Ag paste or Ag film and the necessary sinter equipment are being developed to accelerate the industrialization of silver sinter technology. In this paper, we report the results of a silver sinter film based die attach process evaluation, suitable for IGBT power module production. The proposed process has very good controllability and has the potential for large scale production. The Ag sinter joint porosity and bondline were analyzed by cross section SEM. Thermal shock and cumulative structure function from T3ster measurement both showed superior performance than conventional solder die attach. Thermal structure function analysis showed that Ag sinter die attach layer is a high thermal conductivity region in a IGBT power module system, unlike solder die attach layer which is traditionally accepted as a low thermal conductivity region in a power module system. © 2017 IEEE.


Bai Y.,CAS Institute of Microelectronics | Li C.,ZhuZhou CRRC Times Electrical CO. | Shen H.,CAS Institute of Microelectronics | Yang C.,CAS Institute of Microelectronics | And 2 more authors.
Materials Science Forum | Year: 2017

The 4H-SiC ultraviolet detector of the MESFET structure with gain is proposed and simulated in this paper. The Schottky gate of MESFET is transparent or semi-transparent to allow more of the incident UV light to be absorbed in the device. The effect of the doping and thickness of the channel layer on the photocurrent of the 4H-SiC MESFET UV detector is simulated and the effect mechanism is analyzed. The simulation results show that the 4H-SiC MESFET exhibits photocurrent below 380 nm. And only when the channel of the 4H-SiC MESFET is in the open state there will be a gain in the detector. Shorter gate length is beneficial to improve the responsivity and the gain of the 4H-SiC MESFET UV detector. When the gate length is set to 10 μm with the channel thickness of 0.3 μm and channel doping of 1×1017 cm-3, the peak responsivity and the gain are calculated to be 12.9 A/W and 55.6 respectively. © 2017 Trans Tech Publications, Switzerland.


Zhang M.,Hong Kong Polytechnic University | Wei J.,Hong Kong University of Science and Technology | Jiang H.,Dynex Semiconductor | Jiang H.,Zhuzhou CRRC Times Electrical Co. | And 2 more authors.
IEEE Transactions on Device and Materials Reliability | Year: 2017

The high OFF-state oxide field in the SiC trench MOSFET is a threat for its long term reliability, and thus hinders the wide acceptance of the SiC trench MOSFETs. In this paper, an SiC trench MOSFET with protruded p-bases (PBMOS) is proposed, which features protruded p-bases to shield the gate oxide at the trench bottom against the high OFF-state drain voltage. Numerical device simulations based on Sentaurus TCAD verify the benefits of the structure. The OFF-state oxide field (Eox-m) in the PB-MOS is 1.7 MV/cm, which is dramatically lower compared to the high Eox-m of 8.6 MV/cm in the conventional trench MOSFET (C-MOS). The above benefit is achieved without sacrificing device performances. The reverse transfer capacitance (Crss) of the PB-MOS is around ten times lower than that in the C-MOS. Both the gate charge (QG) and the gate-to-drain charge (QGD) of the PB-MOS are significantly improved compared to the C-MOS. A low specific ON-resistance (RON) is maintained in the PB-MOS by using additional JFET doping to compensate the JFET effect. As a result, the PB-MOS presents much better figures of merit QG RON and QGD RON than those of the C-MOS. The PB-MOS achieves a much faster switching speed than the C-MOS, and consequently exhibits an appreciable reduction in the switching energy loss. © 2017 IEEE.


Zhang M.,Hong Kong Polytechnic University | Wei J.,Hong Kong University of Science and Technology | Jiang H.,Dynex Semiconductor | Jiang H.,Zhuzhou CRRC Times Electrical Co. | And 2 more authors.
IET Power Electronics | Year: 2017

A SiC trench metal-oxide-semiconductor field-effect transistor (MOSFET) with a self-biased p-shield (SBS-MOS) is proposed and comprehensively studied. The p-shield region is used to reduce the high oxide field at the OFF-state, which would otherwise be detrimental to the device long-term reliability. A self-biasing network is designed to raise the potential of the p-shield in the SBS-MOS, so that the parasitic junction field effect transistor (JFET) is driven synchronously with the MOS-gate. Mixed-mode numerical simulations are carried out to study the performance of the proposed device. The SBS-MOS boasts a reduced specific ON-resistance (RON-SP) compared with the trench MOSFET with a grounded p-shield (GS-MOS), by the reduction of the JFET resistance and/or further down-scaling of the cell size. To synchronously drive the JFET region, only a slightly larger gate charge is required for the SBS-MOS. Therefore, a low OFF-state oxide field, a low RON-SP and a low QGD are simultaneously achieved in the proposed SBS-MOS. © The Institution of Engineering and Technology.


Wei J.,Hong Kong University of Science and Technology | Jiang H.,Dynex Semiconductor | Jiang H.,Zhuzhou CRRC Times Electrical Co. | Jiang Q.,Hong Kong University of Science and Technology | Chen K.J.,Hong Kong University of Science and Technology
Proceedings of the International Symposium on Power Semiconductor Devices and ICs | Year: 2016

A novel GaN/SiC HyFET is proposed as a high-voltage power switch with low ON-resistance and enhanced switching performance. The device combines the merits of SiC vertical devices and GaN lateral HEMTs by utilizing a SiC drift region to sustain high OFF-state voltage and an enhancement-mode AlGaN/GaN heterojunction channel to reduce the channel resistance. Compared with conventional SiC MOSFETs of the same voltage rating, the HyFET exhibits a greatly reduced Ron owing to the high electron mobility in the channel, together with dramatically lower Crss and QG. Furthermore, the HyFET provides a unipolar reverse conduction diode with a smaller operating voltage and superior reverse recovery property. © 2016 IEEE.


Wei J.,Hong Kong University of Science and Technology | Zhang M.,Hong Kong Polytechnic University | Jiang H.,Dynex Semiconductor | Jiang H.,Zhuzhou CRRC Times Electrical Co. | And 2 more authors.
IEEE Electron Device Letters | Year: 2016

We propose a SiC trench/planar MOSFET (TP-MOS) which features a trench channel and a planar channel in one half-cell. Numerical simulations with Sentaurus TCAD have been carried out to study the proposed device architecture. Compared with traditional planar MOSFET (P-MOS), the TP-MOS has a much lower RON owing to the increased channel density. Unlike traditional trench MOSFET (T-MOS) which enables a higher channel density at the price of a high bottom-oxide field in the high-voltage OFF-state, the TP-MOS features bottom p-bases as in the P-MOS that protect the gate oxide from high electric field. The OFF-state oxide field in the TP-MOS is found to be even lower than the P-MOS. In addition, the TP-MOS boasts a low feedback capacitance (Crss) and gate-to-drain charge (QGD), since the coupling between the gate and the drain is suppressed by the collective effects of the top p-bases and the bottom p-bases. The QG of the TP-MOS is nearly the same as the P-MOS, and is much smaller than the T-MOS. Superior figures of merits (QG × RON and QGD × RON) are achieved in the TP-MOS. © 2016 IEEE.


Wei J.,Hong Kong University of Science and Technology | Jiang H.,Dynex Semiconductor | Jiang Q.,Zhuzhou CRRC Times Electrical Co. | Chen K.J.,Hong Kong University of Science and Technology
IEEE Transactions on Electron Devices | Year: 2016

A GaN/SiC hybrid field-effect transistor (HyFET) is proposed as a high-voltage power device that provides a high-mobility lateral AlGaN/GaN channel to reduce the channel resistance and a vertical SiC drift region to sustain the high OFF-state voltage. The performance of the HyFET is evaluated by numerical device simulations. Compared with the conventional SiC MOSFET, the HyFET exhibits a greatly reduced $R-{\mathrm{\scriptscriptstyle ON}}$ together with a low $C-{\mathrm{ GD}}$ and low gate charges. The figures of merit $Q-{\mathrm{ G}}\times R-{\mathrm{\scriptscriptstyle ON}}$ and $Q-{\mathrm{ GD}}\times R-{\mathrm{\scriptscriptstyle ON}}$ of the HyFET are dramatically improved. © 1963-2012 IEEE.


Bai Y.,CAS Institute of Microelectronics | Shen H.,CAS Institute of Microelectronics | Li C.,ZhuZhou CRRC Times Electrical CO. | Tang Y.,CAS Institute of Microelectronics | Liu X.,CAS Institute of Microelectronics
Materials Science Forum | Year: 2016

The n-p-i-n AlGaN solar-blind ultraviolet double heterojunction phototransistor (DHPT) with internal gain is proposed and optimized in this paper. The dependences of spectral responsivity and quantum gain on structure parameters of the AlGaN DHPT are simulated in detail. Then, the polarization effect of AlGaN heterojunction on the performance of AlGaN DHPT is also investigated. Results show that positive polarization charge would enhance the photoresponse of the device, whereas the negative polarization charge would reduce the photoresponse significantly. The reasons for the polarization effect on performance of AlGaN DHPT are discussed. © 2016 Trans Tech Publications, Switzerland.


Bai Y.,CAS Institute of Microelectronics | Li C.Z.,ZhuZhou CRRC Times Electrical CO. | Shen H.J.,CAS Institute of Microelectronics | Tang Y.D.,CAS Institute of Microelectronics | Liu X.Y.,CAS Institute of Microelectronics
Materials Science Forum | Year: 2016

The 4H-SiC n-p-n BJT for ultraviolet detection with high optical gain is proposed and optimized in this paper. The effect of structural parameters of 4H-SiC phototransistor on the performance of the detectors is simulated and the effect mechanism is analyzed. The simulation results show that the 4H-SiC phototransistors detect UV light with a response wavelength below 380 nm. It is suggested that the base parameters are important to the responsivity of the 4H-SiC BJT. With optimized parameters the 4H-SiC UV phototransistor exhibits peak responsivity as high as 4617 A/W corresponding to a quantum gain of 2.2×105 under the bias voltage of 5 V. © 2016 Trans Tech Publications, Switzerland.


Sun Q.,Northeastern University China | Huang B.,Northeastern University China | Li D.,Zhuzhou CRRC Times Electrical Co. | Ma D.,Northeastern University China | Zhang Y.,Northeastern University China
IEEE Transactions on Industrial Informatics | Year: 2016

As system transient stability is one of the most important criterions of microgrid (MG) security operation, and the performance of an MG strongly depends on the placement of its energy storage devices (ESDs); optimal placement of ESDs for improving system transient stability is required for MGs. An MG structure preserving energy function is first developed for voltage source inverter-based MGs since the existing energy functions, based on synchronous generators and the conventional power system, are not applicable for MGs. The concept of internal potential energy of distributed energy resource is presented instead of the kinetic energy term in traditional energy function. Then, a novel approach for the optimal placement of ESDs is proposed based on MG structure preserving energy function for improving MG transient stability. Simulation and experimental results show that the proposed method can be used to find the optimal placement of ESDs and improve the system stability effectively. © 2016 IEEE.

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