Annealing behavior comparison of NTD FZ (H) Si irradiated in light-water-reactor and heavy-water-reactor

Electrical properties and defect annealing behavior of neutron transmutation doping Si (NTD Si) grown by floating-zone (FZ) method in a hydrogen (H) atmosphere were studied by resistivity measurements, optical microscopy and infrared (IR) absorption spectra. The NTD of the crystal silicon ingots was performed in a light-water-reactor [L NTD FZ (H) Si] and a heavy-water-reactor [H NTD FZ (H) Si] respectively. A comparison of annealing behaviors has been made between the L NTD FZ (H) Si and H NTD FZ (H) Si samples. After annealing at ∼480 °C an excess donor concentration has been observed in both crystals, L NTD FZ (H) Si and H NTD FZ (H) Si. The values for the donor decomposition activation energy are about 1.5 and 0.4 eV in the annealing temperature ranges of 500–540, and 580–640 °C, respectively. There is a peripheral lag during the conductivity conversion from p- to n-type in the L NTD FZ (H) Si but not in H NTD FZ (H) Si samples. Hydrogen-related defects (big pits) in H NTD FZ (H) Si samples and micro-defects in L NTD FZ (H) Si samples were observed by optical microscopy.