Papers by Keyword: Reverse Recovery

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Authors: Alex V. Bolotnikov, Peter A. Losee, Kevin Matocha, Jeff Nasadoski, John Glaser, Steve Arthur, Z. Stum, J. Garrett, Ahmed Elasser, Ljubisa Stevanovic, Harsh Naik, T. Paul Chow
Abstract: This paper presents a study of performance and scalability of 8kV SiC PIN diodes focusing on area-dependent yield and sensitivity to material properties variation. Successfully fabricated 18 and 36 mm2 SiC-PiN diodes exhibited avalanche breakdown above 8 kV and < 5V forward voltage drop at 100 A/cm2 current density. The fast switching operation of these diodes up to ~5 kHz frequency is evidenced by reverse recovery measurements with by double-pulse inductive switching tests. The devices exhibit 0.142 and 0.169 uC/cm2 stored charge at room temperature and 125oC, respectively, when turned-off from Jf = 100A/cm2 to Vr = 2.1 kV. The measured diode breakdown voltage exhibited location and size dependent yield, indicating the necessity of material quality improvements for production.
Authors: Chiharu Ota, Johji Nishio, Kazuto Takao, Tetsuo Hatakeyama, Takashi Shinohe, Kazu Kojima, Shin Ichi Nishizawa, Hiromichi Ohashi
Abstract: Previous simulation works and experiments on the loss of 4H-SiC floating junction Schottky barrier diodes (Super-SBDs) show that the loss is related to the doping concentration in the drift region and the pattern of the floating layer. The effect of the doping concentration for lowering the loss is characterized the breakdown voltage (Vbd) and the on-state resistances (RonS) of the Super-SBDs based on Baliga’s figure of Merit (BFOM). Experimental devices with two doping concentrations in the drift region are fabricated to investigate the static characteristics: Vbd and RonS. The Vbd of the Super-SBDs is close to the simulation result, near 3000 V. However the tendency of the Vbd by the doping concentration is not similar to the simulation result. And the RonS are about 3.22 mcm2 which is higher than that of simulation result. The doping concentration optimized in this study does not show significant lowering loss and the design of the floating layer in the termination region affect the low-loss static characteristics of the Super-SBD. In addition, adopting PiN structure with floating layer (Super-PiN) affects the low-loss dynamic characteristics, optimizing the doping concentration in the drift region. We conclude that the fabricated Super-SBDs with the floating layer in the termination region, the drift region with a doping concentration of 1.01016 cm-3 and mesa-shaped termination structure, have excellent Vbd of 2990 V which is almost same as that of simulation result and RonS of 3.22 mcm2.
Authors: Martin Domeij, Bo Breitholtz, P. Liberski, A. Martinez, Peder Bergman
Authors: Koji Nakayama, Atsushi Tanaka, Katsunori Asano, Tetsuya Miyazawa, Masahiko Ito, Hidekazu Tsuchida
Abstract: The forward voltage drops of pin diodes with the carbon implantation process or thermal oxidation process using a drift layer of 120 μm thick are around 4.0 V and are lower than those with the standard process. The reverse recovery characteristics of diodes with the standard process or carbon implantation at room temperature show almost the same tendency. In the reverse recovery characteristics at 250 oC, pin diodes with carbon implantation process, however, have the longer reverse recovery time than those with the standard process. These characteristics indicate that a recombination path other than the bulk carrier lifetime, such as the interfaces or the surface recombination, becomes dominant in the reverse recovery characteristics at room temperature.
Authors: Takashi Tsuji, Akimasa Kinoshita, Noriyuki Iwamuro, Kenji Fukuda, Kazuo Tezuka, Tatsuro Tsuyuki, Hiroshi Kimura
Abstract: The 1200V class silicon carbide Schottky barrier diodes were designed and fabricated. The drift layer resistance was reduced in order to realize low forward voltage drops. Since the low drift layer resistance led to the low breakdown voltage, the avalanche withstanding capability should be enhanced not to cause the destructive breakdown. By means of the optimized device design, we succeeded to realize the low forward voltage drop while maintaining the high avalanche withstanding capability. The forward voltage drops at 200A/cm2 were 1.35V at 25°C and 1.63V at 175°C, respectively. The avalanche withstanding capability was more than 3500mJ/cm2 at 25°C. By substituting SiC-SBDs for Si-pin diodes, the estimated total power loss of the module comprised by Si-IGBTs and the diodes was reduced by 35%. We could also confirm that no failures happened after long term reliability tests.
Authors: Brett A. Hull, Mrinal K. Das, Jim Richmond, Bradley Heath, Joseph J. Sumakeris, Bruce Geil, Charles Scozzie
Abstract: Forward voltage (VF) drift, in which a 4H-SiC PiN diode suffers from an irreversible increase in VF under forward current flow, continues to inhibit commercialization of 4H-SiC PiN diodes. We present our latest efforts at fabricating high blocking voltage (6 kV), high current (up to 50 A) 4H-SiC PiN diodes with the best combination of reverse leakage current (IR), forward voltage at rated current (VF), and VF drift yields. We have achieved greater than 60% total die yield onwafer for 50 A diodes with a chip size greater than 0.7 cm2. A comparison of the temperature dependent conduction and switching characteristics between a 50 A/6 kV 4H-SiC PiN diode and a commercially available 60 A/4.5 kV Si PiN diode is also presented.
Authors: Koji Nakayama, Shuji Ogata, Toshihiko Hayashi, Tetsuro Hemmi, Atsushi Tanaka, Toru Izumi, Katsunori Asano, Dai Okamoto, Yasunori Tanaka, Tomonori Mizushima, Mitsuru Yoshikawa, Hiroyuki Fujisawa, Kensuke Takenaka, Manabu Takei, Yoshiyuki Yonezawa, Kenji Fukuda, Hajime Okumura
Abstract: The reverse recovery characteristics of a 4H-SiC PiN diode under higher voltage and faster switching are investigated. In a high-voltage 4H-SiC PiN diode, owing to an increased thickness, the drift region does not become fully depleted at a relatively low voltage Furthermore, an electron–hole recombination must be taken into account when the carrier lifetime is equal to or shorter than the reverse recovery time. High voltage and fast switching are therefore needed for accurate analysis of the reverse recovery characteristics. The current reduction rate increases up to 2 kA/μs because of low stray inductance. The maximum reverse voltage during the reverse recovery time reaches 8 kV, at which point the drift layer is fully depleted. The carrier lifetime at the high level injection is 0.086 μs at room temperature and reaches 0.53 μs at 250 °C.
Authors: Ranbir Singh, Kenneth G. Irvine, Jim Richmond, John W. Palmour
Authors: Peter A. Losee, Can Hua Li, R.J. Kumar, T. Paul Chow, I. Bhat, Ronald J. Gutmann, Robert E. Stahlbush
Abstract: The on-state and switching performance of high voltage 4H-SiC junction rectifiers are compared using numerical simulations and experimental characterization. Epitaxial and implanted anode PiN diodes as well as novel, advanced rectifiers have been fabricated in 4H-SiC using 110μm thick drift layers. The relatively low forward voltage drop of these epi-anode diodes (4.2V @ 100A/cm2) indicates moderate conductivity modulation, while the superior switching performance of the “MPS-like” rectifiers is demonstrated with reverse recovery characteristics at various temperatures and forward current densities.
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