The evaluation of radiation damaged epitaxial silicon

A technique has been developed for the determination of the concentration and Hall mobility of majority carriers in n on p homoepitaxial silicon using micro-Hall samples. These devices are essentially the same size as monolithic integrated circuits, and, since junction isolated integrated circuit processes are used in the manufacture of these samples, they have the properties of as-processed integrated-circuit materials. After initial characterization, the samples were exposed to pulse reactor spectrum neutron fluences at room temperature. Subsequent characterization permitted the determination of majority carrier removal rates and mobility dagradation. As expected, the carrier removal rate for epitaxial silicon at the onset of electrically observable displacement damage is essentially the same as that for bulk silicon with the same resistivity, 2.65 neutrons^-1cm^-1. Mobility degradation is not significant at room temperature. Low-temperature characterization indicates the importance of damage clusters on mobility when charge scattering dominates over lattice scattering.