Pretreatment Method for Reduction and/or Elimination of Basal Plane Dislocations Close to Epilayer/Substrate Interface in Growth of SiC Epitaxial Films

Description:

Reference #: 00932

The University of South Carolina is offering licensing opportunities for an optimized process for the pre-treatment of the SiC substrate to reduce or eliminate basal plane dislocation and in-grown stacking faults in SiC epitaxial films for the fabrication of state of the art electronics and optical devices. This process offers significant advantages over current techniques because it preserves high BPD conversion rate and is simple (three-minute treatment), non-destructive, and highly efficient process.

Advantages and Benefits:

  • Simple, non-destructive, fast, and highly efficient process

  • Preserves a high BPD conversion rate

Potential Applications:

This technology is used in fabrication of high voltage and high power electronics.

Problem:

In SiC bipolar devices, basal plane dislocations (BPDs) in the active region generate Shockley-type stacking faults (SFs) and increase the forward voltage drift. For a sufficient yield of bipolar devices, the density of these performance-limiting defects in the epitaxial layer must be limited. One current method to reduce BPDs employs a defect selective etch of the SiC substrate by conventional molten KOH prior to epitaxial growth. However, this method severely degrades the epilayer. The epilayer must then be polished before device fabrication. Recently, a "growth-etch-regrowth" method was developed to achieve a BPD-free epilayer with almost no surface degradation. However, this method doubled the number of steps in epigrowth. Therefore, there was a need for a practically improved method of reducing BPDs in a SiC epitaxial film without substantially, adversely affecting the surface morphology of the SiC substrate.

Invention Description:

This process has been developed and optimized for non-destructive pre-treatment of the SiC substrate. The technique allows the pre-treatment of the SiC substrate for reduction or elimination of basal plane dislocation and in-grown stacking faults in SiC epitaxial films. The method is a simple (three-minute treatment), non-destructive, and highly efficient process for the reduction of BPDs and SFs in the epitaxial film. It preserves a high BPD conversion rate. It shows high potential to be applied as one of the routine treatment steps prior to SiC epitaxial growth, which is one of the most important steps to fabricate various "state of the art" electronic and optical devices.

Patent Information:
Title App Type Country Serial No. Patent No. File Date Issued Date Expire Date Patent Status
Pretreatment Method for Reduction and/or Elimination of Basal Plane Dislocations Close to Epilayer/Substrate Interface in Growth of SiC Epitaxial Films Utility United States 13/682,240 8,900,979 11/20/2012 12/2/2014 11/20/2032  
For Information, Contact:
Technology Commercialization
University of South Carolina
technology@sc.edu
Inventors:
Tangali Sudarshan
Haizheng Song
Keywords:
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