Enhanced displacement damage effectiveness in irradiated silicon devices

Measurements and analyses have been performed to investigate enhanced displacement damage effectiveness in charge-coupled devices irradiated with 14-MeV neutrons and with 100-MeV protons. The thermal activation energies associated with single-particle-induced dark current events are observed to vary over the range 0.3-0.7 eV, with anomalously large events exhibiting relatively small values (≲0.4 eV). The data are described in terms of three mechanisms: conventional thermal generation in moderate-field regions, thermal generation over a reduced barrier in high-field regions, and phonon-assisted tunneling in the latter regions. Data and analyses indicate that the effectiveness of single-particle-induced displacement damage in producing dark current depends on the local electric field strength in the region in which the damage is introduced in a given device. These findings suggest that enhanced displacement damage effects will become more important as integrated circuit geometries are reduced