Energy Dependence of Proton Displacement Damage Factors for Bipolar Transistors

Displacement damage factors, p, have been measured as a function of collector current for proton irradiations of 2N2222A (npn) and 2N2907A (pnp) switching transistors and 2N3055 (npn) power transistors over the energy range 5.0 to 60.3 MeV. The measurements of Kp were made on specially selected lots of devices and were compared to values of the neutron damage factors, Kn, for 1 MeV displacement damage equivalent neutrons made on the same devices. The results show that so far as device operation is concerned, the nature of the displacement damage produced by high energy protons and by fission neutrons is essentially the same. Over the energy range studied, protons were found to be more damaging than neutrons. For 5.0 MeV protons Kp/Kn was about 8.5 compared to about 1.8 for 60.3 MeV protons.