Conclusion

For the practical purpose QS - characteristics of implanted gate devices can be well fitted assuming traps at the gate/oxide interface. A second possibility is to assume a drop in the gate doping very close to the gate/oxide interface. When the QS - curve is fitted, the calculated integral quantities like the inversion-layer charge, the oxide field and the drain current agree well with experimental results.

There are additional physical phenomena in the gate not included in the model. We think there is no reason to model gate depletion, an essentially parasitic effect, assuming complex physical formulations. We would like to point out, however, that the phenomena 5) and 6) discussed in this section, may come into play in the bulk of future devices with thin oxides and increased bulk doping. A more complete both, physical and engineering description of the space-charge regions accounting for these phenomena, is required to accurately model these devices.