It will be understood that these equations are for a simplified model of temperature dependence
Measurement for a normal polysilicon resistor shows that the thermal activation energy Ea is approximately 0.5 electron volts (eV) when the resistance is in the range used for load resistors, 0.1 to 50 gigaohms (See also, Fig. 5). When the thermal activation energy is decreased below 0.5 eY for prior art polysilicon resistors, the resistance falls below the useful range.