Electrical characteristics of boron-implanted n-channel MOS transistors for use in logic circuits

Adapted formulas describing the current-voltage relationship of MOS transistors with nonuniform substrate doping are presented. Only the case Where, at zero background polarization, the depletion layer is larger than the implanted impurity depth, is considered. Attention is given to the experimental determination of the effective mobility, the space-charge-layer depth and, if the impurity profile is inown, of the surface potential, the flatband voltage, and the maximum allowable dose for low bulk effect. Experiments are in good agreement with the calculations. Deviations between theory and experiment for small gate voltages are observed in the intermediate region between weak and strong inversion.