Effects of Different Defect Types on the Performance of Devices Fabricated on a 4H-SiC Homoepitaxial Layer

An 8° off-axis 4H-SiC wafer with circular Schottky contacts fabricated on a CVD grown 4H-SiC homoepitaxial layer was studied to investigate the influence of various defects, including small (closed-core) screw dislocations (Burgers vector of 1c or 2c), hollow-core (micropipes; Burgers vector larger than 2c), threading edge dislocations (from conversion of basal plane dislocations from the substrate into the epilayer), grain boundaries and triangular defects, on the device performance in the form of breakdown voltages. The defects were examined using synchrotron white beam x-ray topography (SWBXT) based techniques and molten KOH etching. The devices commonly contained basal plane dislocations, small screw dislocations and threading edge dislocations, the latter two of which could give rise to low breakdown voltages for the devices. In addition, less commonly observed defects such as micropipes, grain boundaries and triangular defects are much more destructive to device performance than closed-core screw dislocations and threading edge dislocations.

[1]  Y. Shishkin,et al.  High growth rates (>30 μm/h) of 4H–SiC epitaxial layers using a horizontal hot-wall CVD reactor , 2005 .

[2]  S. Maximenko,et al.  Stacking fault nucleation sites in diffused 4H-SiC p‐i‐n diodes. , 2005 .

[3]  H. Tsuchida,et al.  Analysis of Structural Defects in the 4H-SiC Epilayers and their Influence on the Electrical Properties , 2004 .

[4]  Kibog Park,et al.  Quantum well state of self-forming 3C−SiC inclusions in 4H SiC determined by ballistic electron emission microscopy , 2004 .

[5]  Tsunenobu Kimoto,et al.  Crystallographic defects under device-killing surface faults in a homoepitaxially grown film of SiC , 2003 .

[6]  M. Dudley,et al.  Contribution of x-ray topography and high-resolution diffraction to the study of defects in SiC , 2003 .

[7]  Marek Skowronski,et al.  Dislocation conversion in 4H silicon carbide epitaxy , 2002 .

[8]  A. Ellison,et al.  Influence of epitaxial growth and substrate-induced defects on the breakdown of 4H–SiC Schottky diodes , 2000 .

[9]  R. Glass,et al.  Status of Large Diameter SiC Crystal Growth for Electronic and Optical Applications , 2000 .

[10]  C. Carter,et al.  Direct evidence of micropipe-related pure superscrew dislocations in SiC , 1999 .

[11]  P. Pirouz,et al.  The Origin of Triangular Surface Defects in 4H-SiC CVD Epilayers , 1997 .

[12]  H. Matsunami,et al.  Analysis of Schottky Barrier Heights of Metal/SiC Contacts and Its Possible Application to High‐Voltage Rectifying Devices , 1997 .

[13]  Michael Dudley,et al.  White-beam synchrotron topographic studies of defects in 6H-SiC single crystals , 1995 .

[14]  H. Morkoç,et al.  Large‐band‐gap SiC, III‐V nitride, and II‐VI ZnSe‐based semiconductor device technologies , 1994 .

[15]  Yu Wang,et al.  Correlation Between Morphological Defects, Electron Beam Induced Current Imaging, and the Electrical Properties of 4H-SiC Schottky Diodes , 2005 .

[16]  K. Koga,et al.  Growth and Characterization of 6H-SiC Bulk Crystals by the Sublimation Method , 1992 .