A model for the capacitance—Voltage characteristics of MODFET´s

Using Fermi-Dirac statistics, a model for the gate capacitance-voltage characteristics of MODFET´s is developed that includes not only the capacitance component due to two-dimensional electron gas density but also the capacitance component due to donor neutralization. To analytically solve Poisson´s equation with the Fermi-Dirac statistics, we analyzed the theory by using two regions (the complete ionization region and the partial ionization region of doped impurities). Using the obtained C-V relationships, the gate capacitance is calculated with the numerical calculation method. The results are in good agreement with experimental data.