For the polysilicon gate, as the doping concentration is extremely high, the heavily doped n-type gate material can be assumed to be degenerate. That is, the Fermi level E_F is almost coincident with the bottom of the conduction band E C . Hence, assuming that the intrinsic energy level E_I is at the middle of the band gap, the potential difference between E_I and E_F for the gate is = ½ (energy band gap of Si) = 1/2 X 1.1 = 0.55 V.

Thus, the work function difference between the doped polysilicon gate and the p-type substrate is -0.35 V - 0.55 V = -0.90 V.

The depletion charge density at V_SB =0 is

The oxide-interface charge density is

The gate oxide capacitance per unit area is (using dielectric constant of SiO₂ as 3.97)