Question 4. Determine the Doping Density of the Silicon Substrate

    Again, looking at the C-V plot for the MOS capacitor, the minimum capacitance, C_min is given as the series contribution of oxide and depletion capacitor, as

   (1)

    Also 

                  (2)

    C_dep can be expressed as follows:

   (3)

    Where

    (4)

    Replacing all the variables in Equation (1) to (4), the doping density of the silicon substrate is found to be:

   (5)

    Clearly, it cannot be solved by ordinary method, thus the MATLAB is used to solve the equation.The result is shown:

 (7)

    The detailed discussion will be given in the final report.