Papers by Author: Petre Alexandrov

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Authors: Yu Zhu Li, Petre Alexandrov, Jian Hui Zhang, Larry X. Li, Jian Hui Zhao
Abstract: SiC JFET, compared with SiC MOSFET, is attractive for high power, high temperature applications because it is free of gate oxide reliability issues. Trenched-and-Implanted VJFET (TIVJFET) does not require epi-regrowth and is capable of high current density. In this work we demonstrate two trenched-and-implanted normally-off 4H-SiC vertical junction field-effect transistors (TI-VJFET), based on 120μm, 4.9×1014cm-3 and 100μm, 6×1014cm-3 drift layers. The corresponding devices showed blocking voltage (VB) of 11.1kV and specific on-resistance (RSP_ON) of 124m7cm2, and VB of 10kV and RSP_ON of 87m7cm2. A record-high value for VB 2/RSP_ON of 1149MW/cm2 was achieved for normally-off SiC FETs.
Authors: Jian Hui Zhang, Petre Alexandrov, Jian Hui Zhao
Abstract: This paper reports a newly achieved best result on the common emitter current gain of 4H-SiC high power bipolar junction transistors (BJTs). A fabricated 1600 V – 15 A 4H-SiC power BJT with an active area of 1.7 mm2 shows a high DC current gain (b) of 70, when it conducts 9.8 A collector current at a base current of only 140 mA. The maximum AC current gain (DIC/DIB) is up to 78. This high performance BJT has an open base collector-to-emitter blocking voltage (VCEO) of over 1674 V with a leakage current of 1.6 μA, and a specific on-resistance (RSP-ON) of 5.1 mW.cm2 when it conducts 7.0 A (412 A/cm2) at a forward voltage drop of VCE = 2.1 V. A large area 4H-SiC BJT with a footprint of 4.1 mm x 4.1 mm has also shown a DC current gain over 50. These high-gain, high-voltage and high-current 4H-SiC BJTs further support a promising future for 4H-SiC BJT applications.
Authors: Jian Hui Zhang, Jian Wu, Petre Alexandrov, Terry Burke, Kuang Sheng, Jian Hui Zhao
Abstract: This paper reports recent progress in the development of high power 4H-SiC BJTs based on an improved device design and fabrication scheme. Near theoretical limit high blocking voltage of VCEO=1,836 V has been achieved for 4H-SiC BJTs based on a drift layer of only 12 μm, doped to 6.7x1015 cm-3. The collector current measured for a single cell BJT with an active area of 0.61 mm2 is up to IC=9.87 A (JC=1618 A/cm2). The collector current is 7.64 A (JC=1252 A/cm2) at VCE=5.9 V in the saturation region, corresponding to an absolute specific on-resistance (RSP_ON) of 4.7 m9·cm2. From VCE=2.4 V to VCE= 5.8 V, the BJT has a differential RSP_ON of only 3.9 m9·cm2. The current gain is about 8.8 at Ic=5.3 A (869 A/cm2). This 4H-SiC BJT shows a V2/RSP_ON of 717 MW/cm2, which is the highest value reported to date for high-voltage and high-current 4H-SiC BJTs. A verylarge area 4H-SiC BJT with an active area of 11.3 mm2 is also demonstrated.
Authors: Yu Zhu Li, Leonid Fursin, J. Wu, Petre Alexandrov, Jian Hui Zhao
Authors: J. Wu, Leonid Fursin, Yu Zhu Li, Petre Alexandrov, Jian Hui Zhao
Authors: Jian Hui Zhao, Leonid Fursin, Petre Alexandrov, Larry X. Li, M. Weiner
Authors: Petre Alexandrov, B. Wright, M. Pan, M. Weiner, Leonid Fursin, Jian Hui Zhao
Authors: Jun Hu, Xiao Bin Xin, Petre Alexandrov, Jian Hui Zhao, Brenda L. VanMil, D. Kurt Gaskill, Kok Keong Lew, Rachael L. Myers-Ward, Charles R. Eddy
Abstract: This paper reports a 4H-SiC single photo avalanche diode (SPAD) operating at the solar blind wavelength of 280 nm. The SPAD has an avalanche breakdown voltage of 114V. At 90% and 95% of the breakdown voltage, the SPAD shows a low dark current of 57.2fA and 159fA, respectively. The quantum efficiency of 29.8% at 280nm and <0.007% at 400nm indicates a high UV-to-visible rejection ratio of >4300. Single photon counting measurement at 280nm shows that a single photon detection efficiency of 2.83% with a low dark count rate of 22kHz is achieved at the avalanche breakdown voltage of 116.8V.
Authors: Jun Hu, Larry X. Li, Petre Alexandrov, Xiao Hui Wang, Jian Hui Zhao
Abstract: 4H-SiC Junction Barrier Diodes (JBS) diodes were designed, fabricated and tested. The JBS diodes based on a 45μm thick, 1.4×1015cm-3 doped drift layer with multiple non-uniform spacing guard ring edge termination showed a blocking voltage of over 5kV. The 5kV JBS diode has a forward current density of 108A/cm2 at 3.5V and a specific on resistance (RSP_ON) of 25.2mW·cm2, which is very close to the theoretical RSP_ON of 23.3mΩ·cm2. DC I-V measurement of packaged JBS diodes showed a forward current of 100A at a voltage drop of 4.3V. A half-bridge inverter with a bus voltage up to 2.5kV was used to characterize the high power switching performance of SiC JBS diodes. A large inductance load of 1mH was used to simulate the load of a high power AC induction motor. Compared to a Si PIN diode module, the SiC JBS package reduces diode turn-off energy loss by 30% and Si IGBT turn-on energy loss by 21% at room temperature.
Authors: Petre Alexandrov, Anup Bhalla, Zhong Da Li, Xue Qing Li, John Bendel, Jonathan Dodge
Abstract: We present a SiC Trench JFET technology that achieves a record setting specific on-resistance (RDSA) of 0.75mohm.cm2. These SiC devices are combined with optimized low voltage MOSFETs to form co-packaged cascode transistors, which provide unprecedented performance benefits, with a clear path to direct cost parity with silicon superjunction devices. These devices are shown to be useful for all circuit topologies..
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