The effect of heavy boron doping on oxygen precipitation in Czochralski silicon substrates of epitaxial wafers has been studied with transmission electron microscopy observations and a preferential etching method. Prolonged isothermal annealing between 700 and 1000°C for up to 700 h was performed on p/p+ (5–20 mΩ cm) and p/p− (10 Ω cm) wafers. It was found that, with an increase in boron concentration, the precipitate density increased, and the precipitates could nucleate at a higher temperature. The growth process of platelet precipitates was also investigated and compared with the process in polished p− wafers. It was confirmed that precipitate growth rate in p/p+ wafers was higher than that in p− wafers, and precipitate nucleation in p/p− wafers was delayed compared with p/p+ wafers. The precipitate growth in p/p+ wafers was determined to be reaction‐limited, which differed from the diffusion‐limited growth in p− wafers. © 2000 The Electrochemical Society. All rights reserved.
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