A technique is proposed to extract the reverse saturation current parameter and ideality factor of semiconductor junctions from the low forward voltage region of the device's characteristics, even under the presence of significant parallel resistance effects. The series combination of two ideal diodes is proposed for modeling real devices with a nonlinear contact resistance, in which case, the effective ideality factor at high voltage is higher than that of low voltage. It is proved, under certain physical assumptions, that the series combination of two ideal diodes can be modeled as a single effective diode for low voltage and another effective diode for high voltage. Both techniques were tested and their accuracy verified on experimental and simulated I V characteristics.