Characterization and modeling of high voltage SiC PN diode

Silicon carbide is seen as a potent material for high power, high temperature and harsh environment applications because of its large band-gap, the consequently greater breakdown electric field, higher thermal conductivity and electron saturation velocity. However the commercial use of SIC devices is prohibited by the immature process technology and wafer quality deficiencies. While the most degrading micropipe defects have been significantly reduced in number, other defect types like screw dislocations continue to contaminate SiC devices in large quantities. This paper models the presence of embedded screw dislocation type defects for SiC PN junction diodes. The defects are presented as parallel diodes to the ideal ones with areas correspondingly reduced. Since the defects affect the I-V characteristics severely, these are studied in detail. Defect diodes are shown to turn on earlier to the ideal ones depending upon their built-in voltage, thus giving an anomalous bump in the initial part of forward I-V curves. The extracted diode structure is simulated in a 2-D finite element simulator and the static characteristics and forward I-V curves matched. Reverse recovery characteristics are also studied and found to vary very slightly with forward current.

[1]  Tsunenobu Kimoto,et al.  Performance limiting surface defects in SiC epitaxial p-n junction diodes , 1999 .

[2]  C. Fazi,et al.  Positive temperature coefficient of breakdown voltage in 4H-SiC pn junction rectifiers , 1997, IEEE Electron Device Letters.

[3]  H. Mitlehner,et al.  SiC devices: physics and numerical simulation , 1994 .

[4]  Michael Dudley,et al.  Breakdown Degradation Associated With Elementary Screw Dislocations In 4H-SiC P + N Junction Rectifiers , 1997 .

[5]  Current-controlled negative resistance (CCNR) in SiC P-i-N rectifiers , 1999 .

[6]  O. Noblanc,et al.  Barrier inhomogeneities and electrical characteristics of Ti/4H-SiC Schottky rectifiers , 1999 .

[7]  Michael Dudley,et al.  Study of bulk and elementary screw dislocation assisted reverse breakdown in low-voltage (<250 V) 4H-SiC p/sup +/-n junction diodes. I. DC properties , 1999 .

[8]  Michael Dudley,et al.  Non-Micropipe Dislocations in 4H-SiC Devices: Electrical Properties and Device Technology Implications , 1998 .

[9]  V. Khemka,et al.  Carrier Lifetime Extraction from a 6H-SiC High Voltage p-i-n Rectifier Reverse Recovery Waveform , 1997 .

[10]  M. Kazimierczuk,et al.  High-temperature dynamic characterization of 4H-silicon carbide p-n diodes , 1996, IECEC 96. Proceedings of the 31st Intersociety Energy Conversion Engineering Conference.

[11]  Krishna Shenai,et al.  Optimum semiconductors for high-power electronics , 1989 .

[12]  J. D. Parsons,et al.  Fast Risetime Reverse Bias Pulse Failures in SiC PN Junction Diodes , 1996 .