A new punchthrough current model based on the voltage-doping transformation

The punchthrough phenomenon is investigated by a 2-D numerical analysis. A physical interpretation that relates this phenomenon to the drain-field-induced reduction in doping concentration is proposed. This interpretation allows a better understanding of the mechanism of surface and bulk punchthrough flows and provides a guideline for the quantitative solution to the problem. The relation between the reduced N* and real N dopings (called the voltage-doping transformation, or VDT) is derived from the two-dimensional Poisson equation. It is shown that as a result of the VDT, it is possible to accurately calculate the actual barrier heights as a function of applied voltages and channel length using the well-known long-channel expressions where N is substituted by N*.<
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