NPN bipolar device with surface mount package was selected as the research object in this paper. By setting the equilibrium material and measuring the radiation sensitive electrical parameters of the device during the radiation experiment

the impact of equilibrium material on the total ionization dose effect of bipolar device was studied. The results show that the current gain degradation of bipolar devices with equilibrium material was more obvious than that without equilibrium material

and only setting the front equilibrium material has a greater impact than only setting the back equilibrium material. In the three different equilibrium materials conditions (front and back

front only

and back only)

the devices current gain degradation differences were 22.55%

13.38%

and 12.58 at the 50 krad (Si) dose point and decreased to 11.65%

7.31%

and 4.14% when the total irradiation dose reached 300 krad (Si) respectively. Therefore

in the process of evaluating the radiation hardness level of electronic device

it is necessary to conduct irradiation tests in the device according to the device's structural size

set a certain thickness of the equilibrium material

so that the device sensitive area to meet the secondary electron equilibrium conditions

so as to ensure that the device sensitive area of the actual absorbed dose to reach the nominal irradiation dose.