High-Resolution Photoinduced Transient Spectroscopy of Electrically Active Iron-Related Defects in Electron Irradiated High-Resistivity Silicon

High-resolution photoinduced transient spectroscopy (HRPITS) has been employed to investigate iron-related point defects produced by electron irradiation in high-resistivity silicon. The measurements revealed 16 traps with activation energies ranging from 14 to 530 meV. From the comparison of results, obtained by the HRPITS and ESR measurements performed on the same samples, a trap positioned at E_v+500 meV was attributed to the iron-vacancy pair (Fe_i)V and that positioned at E_V+530 meV to the vacancy complex with two iron atoms (Fe_i)₂V. The former is found to be stable at 400°C, while the latter anneals out at this temperature similarly to the trap at E_V+410 meV related to interstitial iron. As a result of the transformation of the (Fe_i)₂V complex and reactions of the interstitial iron with native defects, new iron-related traps with activation energies of 85, 220 and 380 meV are formed.