Electron Paramagnetic Resonance of Erbium Doped Silicon

Electron paramagnetic resonance measurements have been made on samples of float zone silicon, implanted with 10(15) Er/cm(2), One sample was coimplanted with oxygen to give an impurity concentration of 10(20) O/cm(3) and 10(19) Er/cm(3). In this coimplanted sample, sharp lines are observed which are identified as arising from a single spin 1/2 Er3+ center having ag tensor exhibiting monoclinic C-1h symmetry. The principal g values and tilt angle are g(1) = 0.80, g(2) = 5.45, g(3) = 12.60, and tau = 2.6 degrees. In the absence of O, the sharp lines are not observed. No Er3+ cubic centers were detected in either sample. Possible structures for the center are discussed.