We investigated the impact of defect states on the measured forward current-voltage (I-V) curves of ion-implanted planar 4H-SiC p-i-n diodes of a different anode dimension by means of a fine-tuned numerical model. Cross sections and activation energies of defects related to the carbon vacancy (EH 6/7 and Z 1/2 ) and Titanium (Ti) impurity used in our model were experimentally identified in the diodes of the same batch. We analyzed the effect of each individual defect on the I-V curves and estimated the unknown hole capture cross sections by ensuring the optimal match between simulated and measured currents. Small discrepancies between measured and simulated forward current-voltage curves of diodes of equal shape but a different perimeter-to-area ratio has been accounted for by considering, in the simulations, the presence of a fixed positive charge at the diode surface. By using this procedure, diodes of …