Semiconductor device damage due to electrostatic discharge often results from second breakdown, an abrupt increase in current with a drop in voltage. Thus there is a clear need to be able to predict and screen for second breakdown of semiconductors from the basic device parameters. A computer analysis shows that diode areas, widths, and doping levels are required to predict second breakdown powers. These three parameters can be obtained from low-power reverse and forward current-voltage static characteristics. A new disclosure is that the forward-biased silicon diode shows a transition from a quadratic to linear current dependence upon voltage at moderate currents. The diode width can be obtained from the transition voltage.