Problem
Consider a SiC P+/N-/N+ structure where the N- layer doping is 10^16 cm-3 , and the thickness of the layer is 4 . Assume P+ and N+ regions are heavily doped (i.e. you can ignore any potential drop in these regions in your calculations). Assuming a critical breakdown field of 2 MV/cm. The bandgap of SiC is 3.2 eV, and you can assume NC =NV =10^18 cm-3 .
1. Sketch the equilibrium charge, field, and energy band diagrams. Will the N- region be fully depleted at equilibrium?
2. Sketch the charge and field diagram for the reverse bias condition when the N- region is fully depleted. Estimate the reverse voltage when this would happen, and the peak electric field.
3. Estimate the breakdown voltage of the structure. What will be the field distribution under this condition?
4. Estimate the unipolar on-resistance of this structure (in Ohm-cm2 ), assuming most of the resistance is due to the N- region.