Authors: Jian Hui Zhang, Jian Hui Zhao, Xiao Hui Wang, Xue Qing Li, Leonid Fursin, Peter Alexandrov, Mari Anne Gagliardi, Mike Lange, Christopher Dries
Abstract: This paper reports our recent study on 4H-SiC power bipolar junction transistors (BJTs) with deep mesa edge termination. 1200 V – 10 A 4H-SiC power BJTs with an active area of 4.64 mm2 have been demonstrated using deep mesa for direct edge termination and device isolation. The BJT’s DC current gain () is about 37, and the specific on-resistance (RSP-ON) is ~ 3.0 m-cm2. The BJT fabrication is substantially simplified and an overall 10% reduction in the device area is achieved compared to the multi-step JTE-based SiC-BJTs.
710
Authors: Reza Ghandi, Benedetto Buono, Martin Domeij, Carl Mikael Zetterling, Mikael Östling
Abstract: In this work, implantation-free 4H-SiC bipolar transistors with two-zone etched-JTE and improved surface passivation are fabricated. This design provides a stable open-base breakdown voltage of 2.8 kV which is about 75% of the parallel plane breakdown voltage. The small area devices shows a maximum dc current gain of 55 at Ic=0.33 A (JC=825 A/cm2) and VCESAT = 1.05 V at Ic = 0.107 A that corresponds to a low ON-resistance of 4 mΩ•cm2. The large area device shows a maximum dc current gain of 52 at Ic = 9.36 A (JC=312 A/cm2) and VCESAT = 1.14 V at Ic = 5 A that corresponds to an ON-resistance of 6.8 mΩ•cm2. Also these devices demonstrate a negative temperature coefficient of the current gain (β=26 at 200°C) and positive temperature coefficient of the ON-resistance (RON = 10.2 mΩ•cm2).
706
Authors: Jeff B. Casady, David C. Sheridan, Robin L. Kelley, Volodymyr Bondarenko, Andrew Ritenour
Abstract: Equivalent sized (4.5 mm2 die area), 1200 V, 4H-SiC, vertical trench Junction Field Effect Transistors (JFETs) were characterized in terms of DC and switching performance. The 100 mΩ Enhancement-Mode (EM) JFET was found to have natural advantages in safe operation being normally-off, whereas the Depletion-Mode (DM) JFET was found to have advantages with ~ twice as high saturation current, less on-resistance (85 mΩ) and no gate current required in the on-state. The JFETs were found to both have radically less (five to ten times) switching energies than corresponding 1200 V Si transistors, with the DM JFET and EM JFET having EON and EOFF of only 115 µJ and 173 µJ, respectively when tested at half-rated voltage (600 V) and 12 A.
641
Authors: Reza Ghandi, Hyung Seok Lee, Martin Domeij, Benedetto Buono, Carl Mikael Zetterling, Mikael Östling
Abstract: In this study, high voltage blocking (2.7 kV) implantation-free SiC Bipolar Junction Transistors with low on-state resistance (12 mΩ•cm2) and high common-emitter current gain of 50 have been fabricated. A graded base doping was implemented to provide a low resistive ohmic contact to the epitaxial base. This design features a fully depleted base layer close to the breakdown voltage providing an efficient epitaxial JTE without ion implantation. Eliminating all ion implantation steps in this approach is beneficial for avoiding high temperature dopant activation annealing and for avoiding generation of life-time killing defects that reduces the current gain. Also in this process large area transistors showed common-emitter current gain of 38 and open-base breakdown voltage of 2 kV.
833
Authors: Jian Hui Zhang, Leonid Fursin, Xue Qing Li, Xiao Hui Wang, Jian Hui Zhao, Brenda L. VanMil, Rachael L. Myers-Ward, Charles R. Eddy, D. Kurt Gaskill
Abstract: This work reports 4H-SiC bipolar junction transistor (BJT) results based upon our first intentionally graded base BJT wafer with both base and emitter epi-layers continuously grown in the same reactor. The 4H-SiC BJTs were designed to improve the common emitter current gain through the built-in electrical fields originating from the grading of the base doping. Continuously-grown epi-layers are also believed to be the key to increasing carrier lifetime and high current gains. The 4H-SiC BJT wafer was grown in an Aixtron/Epigress VP508, a horizontal hot-wall chemical vapor deposition reactor using standard silane/propane chemistry and nitrogen and aluminum dopants. High performance 4H-SiC BJTs based on this initial non-optimized graded base doping have been demonstrated, including a 4H-SiC BJT with a DC current gain of ~33, specific on-resistance of 2.9 mcm2, and blocking voltage VCEO of over 1000 V.
829
Authors: Jian Hui Zhang, Peter 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.
1155
Authors: Jian Hui Zhao, Jian Hui Zhang, Peter Alexandrov, Larry X. Li, Terry Burke
1173
Authors: Jian Hui Zhao, Jian Hui Zhang, Peter Alexandrov, Terry Burke
1169
Authors: Jian Hui Zhang, Peter Alexandrov, Jian Hui Zhao
1165
Authors: Jian Hui Zhang, Peter Alexandrov, Jian Hui Zhao
1149