A straightforward electrical method to determine screening capability of GOX extrinsics in arbitrary, commercially available SiC MOSFETs

The gate oxide reliability of SiC power MOSFETs can be significantly improved by sorting out devices with critical extrinsic defects using a voltage screening technique. Commonly, higher screening voltages result in more efficient screening and therefore, a lower failure probability due to breakdown of extrinsic defects during the device's lifetime. However, the maximum screening voltage is limited by the onset of irreparable device degradation. Here, we present a simple and straightforward method to determine the irreparable degradation threshold voltage of arbitrary SiC MOSFETs. Our method is based on electrical measurements only, and does not require any specific knowledge about the device structure, gate oxide thickness or other parameters that are often only known to the manufacturers themselves. So, the method can be indirectly used to benchmark the gate oxide reliability by determining the onset voltage of irreparable device damage.