Direct evidence and thermodynamics for the conversion between nitrogen pairs and interstitial nitrogen atoms in nitrogen-doped Czochralski silicon

The conversion between di-interstitial nitrogen (N-2) pairs and interstitial nitrogen (N-i) atoms has long been conceptually presented to understand the nitrogen behaviors in nitrogen-doped Czochralski (NCZ) silicon, unfortunately, lacking direct experimental evidence. In this work, we report on the experimental findings that demonstrate the remarkable dissociation of N-2 pairs into N-i atoms in NCZ silicon quenched from an isothermal anneal at a high temperature in the range of 1050-1250 degrees C. Moreover, it is found that the N-i atoms dissociated from the N-2 pairs at a high temperature can revert to the N-2 pairs at a lower temperature. The aforementioned results have been well understood in terms of thermodynamic analysis and molecular dynamics simulations. We believe that this work gives an insight into the defect engineering in CZ silicon by means of nitrogen-doping.