Shallow thermal donors in silicon doped with isotopic oxygen

The shallow thermal donors (STDs) in silicon doped with isotopic oxygen O-16 and O-18 have been investigated. The sample annealed at 1275 degreesC for 4h in a nitrogen ambient was measured by a Fourier transform infrared (FTIR) spectrometer at 10 K. In comparison, a nitrogen doped Czochralski (NCZ) silicon sample in which nitrogen-oxygen complexes existed was also checked by the FTIR spectrometer. It was found that STDs were formed in the oxygen isotope doped silicon during annealing at high temperature. It is considered that nitrogen could be involved in the generation of STDs. The line positions of the STDs were almost the same as that of the N-O complexes in NCZ silicon. The small shift of some absorption lines of STDs was also observed. In addition, a new unidentified shallow center was found and discussed. (C) 2001 Elsevier Science B.V. All rights reserved.