Grown-in defects limiting the bulk lifetime of p -type float-zone silicon wafers

• Published in: Journal of applied physics Vol. 117; no. 5
• Main Authors: Grant, N. E., Rougieux, F. E., Macdonald, D., Bullock, J., Wan, Y.
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 07.02.2015
• Subjects: Annealing; Applied physics; Constraining; Defects; Diffusion rate; Gettering; Impurities; Silicon; Silicon wafers; Wafers
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.4907804

We investigate a recombination active grown-in defect limiting the bulk lifetime (τbulk) of high quality float-zone (FZ) p-type silicon wafers. After annealing the samples at temperatures between 80 °C and 400 °C, τbulk was found to increase from ∼500 μs to ∼1.5 ms. By isochronal annealing the p-type samples between 80 °C and 400 °C for 30 min, the annihilation energy (Eann) of the defect was determined to be 0.3 < Eann < 0.7 eV. When the annihilated samples were phosphorus gettered at 880 °C or subject to 0.2 sun illumination for 24 h, τbulk was found to degrade. However, when the samples were subsequently annealed at temperatures between 250 and 400 °C, the defect could be re-annihilated. The experimental results suggest that the defect limiting the lifetime in the p-type FZ silicon is not related to fast diffusing metallic impurities but rather to a lattice-impurity or an impurity-impurity metastable defect.