A novel impact-ionization model for 1-µm-MOSFET simulation

In this work, a new formula for the impact-ionization process in silicon is derived. Compared with former descriptions, e.g., Chynoweth's law, this model offers the advantage to accurately calculate the ionization rates even in the case of nonhomogeneous electric fields. The idea of this model takes advantage of Shockley's "lucky-electron" model and the resulting formula is suited for implementation into device simulators to calculate impact-ionization-induced mechanisms. As an example, the model has been used together with the MINIMOS program to calculate the breakdown-voltage improvement of LDD MOSFET's.