Effect of high-temperature electron irradiation on the formation of radiative defects in silicon

Defect formation processes in silicon caused by electron irradiation perfor med at elevated temperatures are studied in detail using photoluminescence (PL) spectroscopy. The use of high temperature during electron irradiation has been found to affect considerably the defect formation process, In part icular, several new unknown excitonic PL lines were discovered in carbon-ri ch Si wafers subjected to electron irradiation at temperatures higher than 450 degrees C, The dominant new luminescent center gives rise to a bound ex citon PL emission at 0.961 eV. The center is shown to be efficiently create d by electron irradiation at temperatures from 450 degrees C up to 600 degr ees C. The electronic structure of the 0.961 eV PL center can be described as a pseudodonor case, where the hole is strongly bound at a level 187 meV above the valence band, while the electron is a effective-mass-like particl e weakly bound by approximate to 21 meV in the BE state, (C) 1999 Elsevier Science B.V. All rights reserved.