The degradation of diffused SiC PIN diodes during forward-biased operation was studied by first fabricating PIN diodes by diffusion of aluminum or boron into 4H-SiC substrates with n-type 10-15 μ m thick epilayers doped by nitrogen up to 5x10(15)cm(-3). The formed diodes were subjected to degradation testing under an applied current density of 200A/cm(2) at room temperature. The majority of the Al diffused diodes demonstrated a voltage drift, &UDelta; V-f, of more than 2 V, while B-doped diodes showed no significant change in forward voltage. The EBIC mode of SEM was employed to monitor nucleation and expansion of stacking faults.