Proton Bombardment of Silicon Semiconductors. Ionization versus Displacement Disablements

摘要

The bombardment of thick silicon crystalline targets by monodirectional and monoenergetic beams of 25 to 250 MeV protons is considered. By use of a proton fluence model that accounts for straggling effects, total ionization dose and silicon atom displacement density particle energy. For assumed values of total dose (1 Mrad (Si) ) and displacement( 10 to the 14th power 1-Mev-equivalent-neutrons/sq cm) levels that would disable typical semiconductors, the times required fora beam of 'reference' proton flux (10 to the 13th power protons/(sq cm) (sec) to disable such devices by each of the two mechanisms are computed. Profiles of the ratio of the two disablement times are presented as functions of incident proton energy. For the reference disablement criteria, ionization disablement is found to precede displacement-disablement. Means to scale results to other values of these criteria are noted. Plans to extend the work to cover all three of the hydrogen iostope beams are noted and the desirability of certain related experimental data is discussed. An appendix details the construction of a function assumed to represent the displacement damage coefficient.