Chemical composition of nitrogen-oxygen shallow donor complexes in silicon

FTIR absorption measurements have been carried out on shallow donor transitions in silicon related to (N, O)-complexes. Growth of a nitrogen-doped float-zone ingot with an axial variation of the interstitial oxygen concentration from <1016 up to 6×1017 cm−3 allowed systematic investigation of the defect formation driven by mass-action laws. The energetically deepest shallow donor of the (N, O)-family has the composition NO. Other species contain up to three oxygen atoms. Implications of the results on the microscopic structure of (N, O)-related shallow donors are discussed.