Enhanced low dose rate sensitivity (ELDRS) experiments were carried out on four commercial bipolar integrated circuits at dose rates ranging from 0.002 to 50 rad(Si)/s. Additionally, pre-irradiation elevated-temperature stress (PETS) experiments were conducted on the same devices at temperatures of 250 °C and 400 °C. The results show that for some devices, the radiation degradation when irradiated at an ultra-low dose rate of 0.002 rad(Si)/s is more than three times greater than that at a common low dose rate of 0.01 rad(Si)/s. Moreover, the maximum enhancement factor of the PETS effects reaches 20.3. It was also discovered that for devices exhibiting PETS effects, the saturation dose rate of ELDRS is less than 0.01 rad(Si)/s. A comprehensive analysis of the composition of the passivation layers indicated that the type and concentration of hydrogen bonds in these layers are the main factors contributing to the experimental outcomes.