Nonionizing energy loss (NIEL) for heavy ions

The concept of nonionizing energy loss (NIEL) has been found useful for characterizing displacement damage effects in materials and devices. Published tabulations, however, are limited with respect to target materials, particle types and energies. In this paper we show how the NIEL database can be significantly expanded to include heavy ions in the coulombic limit by using the Monte Carlo code SRIM. The methodology used to extract NIEL from SRIM is described. This greatly adds to the number of materials and incident particles for which the NIEL concept can be applied. To show that values so derived are consistent with previous calculations, we compare alpha particle NIEL for GaAs derived from SRIM with a direct analytical calculation. The SRIM code is limited in that only coulombic interactions are considered. General rules of thumb are also described which permit prediction of NIEL for any target material over a large energy range. Tabulated values of NIEL for alpha particles incident on Si, GaAs and InP are presented.