Papers by Keyword: Bipolar Diode

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Authors: Pierre Brosselard, Nicolas Camara, Jawad ul Hassan, Xavier Jordá, Peder Bergman, Josep Montserrat, José Millan
Abstract: An innovative process has been developed by Linköping University to prepare the 4HSiC substrate surface before epitaxial growth. The processed PiN diodes have been characterized in forward and reverse mode at different temperature. The larger diodes (2.56 mm2) have a very low leakage current around 20 nA @ 500V for temperatures up to 300°C. A performant yield (68%) was obtained on these larger diodes have a breakdown voltage superior to 500V. Electroluminescence characteristics have been done on these devices and they show that there is no generation of Stacking Faults during the bipolar conduction.
Authors: Bharat Krishnan, Joseph Neil Merrett, Galyna Melnychuk, Yaroslav Koshka
Abstract: In this work, the benefits of the low-temperature halo-carbon epitaxial growth at 1300oC to form anodes of 4H-SiC PiN diodes were investigated. Regular-temperature epitaxial growth was used to form an 8.6 μm-thick n-type drift region with net donor concentration of 6.45x1015 cm-3. Trimethylaluminum doping, in situ during blanket low-temperature halo-carbon epitaxial growth, was used to form heavily doped p-type layers. Forward I-V characteristics measured from diodes having different anode areas indicated that the new epitaxial growth technique provides anodes with low values of the series resistance, even without contact annealing. At room temperature, a 100 μm-diameter diode had a forward voltage of 3.75 V at 1000A/cm² before annealing and 3.23 V after annealing for 2 min at 750°C. The reverse breakdown voltage was more than 680 V (on average) in the devices without edge termination or surface passivation.
Authors: Dethard Peters, Wolfgang Bartsch, Bernd Thomas, R. Sommer
Abstract: The paper compares static and dynamic characteristics of 6.5 kV SiC PiN diodes fabricated with different p-emitters. The version with the thickest p-emitter (4 µm) showed the lowest forward voltage (3.4 V at 100 A/cm²) and the lowest (negative) temperature coefficient. Forward voltage DC stress tests revealed a stability within the measurement error of the test apparatus (<50 mV). The dynamic performance showed a soft recovery even at 4 kV. The reverse recovery charge Qrr is analyzed for different forward currents and junction temperatures. The dynamic losses of the SiC PiN diode are marginal with view to the application in industrial inverters.
Authors: Gabriel Civrac, Farah Laariedh, Nicolas Thierry-Jebali, Mihai Lazar, Dominique Planson, Pierre Brosselard, Jawad ul Hassan, Anne Henry, Erik Janzén, Bertrand Vergne, Sigo Scharnholz
Abstract: This paper reports the fabrication and electrical characterization of PiN diodes on an on-axis grown epitaxial layer. TCAD simulations have been performed in order to design their architecture. Some of these diodes have a breakdown voltage around 600 V. A comparison is made with similar diodes fabricated on off-cut grown layers. Computer simulations are used to explain lower breakdown voltage than those expected.
Authors: Takashi Tsuji, T. Tawara, Ryohei Tanuma, Yoshiyuki Yonezawa, Noriyuki Iwamuro, K. Kosaka, H. Yurimoto, S. Kobayashi, Hirofumi Matsuhata, Kenji Fukuda, Hajime Okumura, Kazuo Arai
Abstract: The authors fabricated pn diodes with Al+ implantation in p-type epitaxial layers, and investigated the influence of the implantation dose on reverse leakage currents. Only in the highest dose with the Al concentration of 2x1020cm-3, more than 90% of the devices showed high leakage currents above 10-4A at the maximum electric field of 3MV/cm. In such devices, almost all of the emissive spots corresponded to threading screw dislocations (TSDs) by the analysis of emission microscopy and X-ray topography. These TSDs were defined as killer defects with the estimated density of 500cm-2 in the case of the highest dose. The emissions were supposed to be due to microplasmas, since the spectra of the emissions were different from those of heat radiation. Condensation of Al atoms, nitrogen atoms and DI defects were excluded as the origin of the emissions by secondary ion mass spectrometry and low temperature photoluminescence analyses.
Authors: Michael E. Levinshtein, Pavel A. Ivanov, John W. Palmour, Anant K. Agarwal, Mrinal K. Das
Abstract: We report on specific features of forward voltage degradation of 4H-SiC p-i-n diodes in the pulse mode. It is shown that pulse stresses with a pulse duration shorter than several milliseconds cause substantially smaller forward voltage drift in comparison with a dc stress with the same charge passed through the diodes and the same distribution of injected carriers. A self-recovery of the forward voltage is observed at room temperature.
Authors: Wolfgang Bartsch, Heinz Mitlehner, S. Gediga
Abstract: In this contribution we summarize measurements on bipolar high voltage SiC-diodes which were fabricated on 4H-SiC wafers preferentially cut 4° off the [0001] basal plane, whereas the p-emitter thickness was varied in predetermined ratios to the n-base thickness. The switching behaviour of optimized 6.5 kV-Diodes at a current level of 25 A is shown at DC link voltages up to 4 kV and at a junction temperature of 125°C. Experimental results are discussed in terms of snappiness.
Authors: Naoya Iwamoto, Shinobu Onoda, Takeshi Ohshima, Kazutoshi Kojima, Atsushi Koizumi, Kazuo Uchida, Shinji Nozaki
Abstract: The effect of electron irradiation on the charge collection efficiency of a 6H-SiC p+n diode has been studied. The diodes were irradiated with electrons of energies from 100 keV to 1 MeV. The charge collection efficiencies of the samples were measured for alpha particles before and after the electron irradiation. The electron irradiation at 100 keV does not affect the charge collection efficiency, while the electron irradiation at 200 keV or higher decreases the charge collection efficiency. The degree of the degradation of the diodes correlates with the energy of the electron irradiation.
Authors: Gil Yong Chung, Mark J. Loboda, Siddarth G. Sundaresan, Ranbir Singh
Abstract: Correlation between carrier lifetime and forward voltage drop in 4H-SiC PiN diodes has been investigated. PiN diodes from the drift layer of 20 m shows breakdown voltage of 3.3 kV and forward voltage drop as low as 3.13 V at 100A/cm2. Variation of calculated forward voltage drop ( ) from measured carrier lifetimes is very comparable to measured of fully processed PiN diodes. Measured carrier lifetime and of PiN diodes also show good spatial correlation. Wafer level lifetime mapping can be employed to assess and predict of PiN diodes.
Authors: Takamitsu Kawahara, Naoki Hatta, Kuniaki Yagi, Hidetsugu Uchida, Motoki Kobayashi, Masayuki Abe, Hiroyuki Nagasawa, Bernd Zippelius, Gerhard Pensl
Abstract: The correlation between leakage current and stacking fault (SF) density in p-n diodes fabricated on 3C-SiC homo-epitaxial layer is investigated. The leakage current density at reverse bias strongly depends on the SF density; an increase of one order of magnitude in the SF density enhances the leakage current by five orders of magnitude at a reverse bias of 400 V. In order to obtain commercially suitable MOSFETs with 10-4Acm-2 at 600V, the SF density has to be reduced below 6×104 cm-2. Photoemission caused by hot electrons, which travel along a leakage path, can be observed at the crossing between a SF and the edge of p-well region; where the maximum electric field is induced. The mechanism of the leakage current is discussed in detail in a separate paper.
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