4H-SiC pin diodes fabricated on epitaxial films grown in-house on various substrates along with devices fabricated on commercial epi-material are presented. Defects have been observed using electroluminescence imaging and are correlated with device electrical performance. Most diodes fabricated with in-house epi-layers up to 25μ m thick show relatively stable forward biased operation, although stacking fault propagation has been confirmed in all samples using electroluminescence imaging. Significant stacking fault propagation induced in the vicinity of testing probes has been observed and resulting design considerations are discussed.