The onset of the high level of injection in MOS structures

The dependence of the inversion charge on the gate voltage in MOS structures has the same behaviour like the diffusion current versus the applied voltage in a pn doped junction. As a similarity, the terms “low level” and “high-level” of injection are extended over the MOS operation. The paper determinates the surface potential, φ_C, that separates the two regimes and demonstrates that its values are greater than the surface potential 2φ_{B with 111...132 m V, for the usual doping concentration of the substrate. These results permit to use the low-level of injection model in MOS structures even in strong inversion condition}