Concerning the onset of heavy inversion in MIS devices

The accepted touchstone for the onset of heavy inversion in metal-insulator-semiconductor (MIS) devices is the condition that the minority carrier density at the surface equals the bulk impurity concentration. It is not always clear how to use that definition in practical problems. In this letter we propose a new definition, and we demonstrate that it leads to the same physical conditions for the onset of heavy inversion as does the heretofore conventional criterion.