Analyses of High Leakage Currents in Al+ Implanted 4H SiC pn Diodes Caused by Threading Screw Dislocations

Takashi Tsuji; T. Tawara; Ryohei Tanuma; Yoshiyuki Yonezawa; Noriyuki Iwamuro; K. Kosaka; H. Yurimoto; S. Kobayashi; Hirofumi  Matsuhata; Kenji Fukuda; Hajime Okumura; Kazuo Arai

doi:10.4028/www.scientific.net/MSF.645-648.913

Paper Titles

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6.5 kV SiC PiN Diodes with Improved Forward Characteristics
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Correlation between Carrier Recombination Lifetime and Forward Voltage Drop in 4H-SiC PiN Diodes
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Optimization of Bipolar SiC-Diodes by Analysis of Avalanche Breakdown Performance
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Analyses of High Leakage Currents in Al⁺ Implanted 4H SiC pn Diodes Caused by Threading Screw Dislocations
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Preliminary Investigation of Laser Induced Photoconductivity in 4H-SiC PiN Diodes and HPSI Substrate
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Charge Collection Efficiency of 6H-SiC P⁺N Diodes Degraded by Low-Energy Electron Irradiation
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4H-SiC PiN Diodes Fabricated Using Low-Temperature Halo-Carbon Epitaxial Growth Method
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Feasibility of Efficient Power Switching Using Short-Channel 1200-V Normally-Off SiC VJFETs; Experimental Analysis and Simulations
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Analyses of High Leakage Currents in Al⁺ Implanted 4H SiC pn Diodes Caused by Threading Screw Dislocations

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.