Forward voltage drop degradation in diffused SiC p-i-n diodes

The time varying relationship between forward voltage drop and temperature in degrading diffused 4H–SiC p-i-n diodes was used to estimate the activation energy (0.34 eV) of the degradation process associated with the formation of stacking faults (SFs). A very strong peak appeared in the electroluminescence spectra at 427 nm and increased steadily in intensity as the forward voltage drop increased. The mismatch stresses, localized in the diffused doped region, are proposed to play a dominant role in the initial formation of SFs. Calculations were performed for the phonon pressure caused by nonradiative carrier recombination, which presumably is responsible for the development and motion of the SFs leading to the observed forward voltage degradation.