Effect of heavy boron doping on oxide precipitate growth in Czochralski silicon

Oxide precipitate growth in boron-doped Czochralski silicon wafers with res istivities ranging from 6 to 40 m Omega cm has been studied following prolo nged annealing from 800 to 1000 degrees C. Transmission electron microscopy revealed that (i) the growth rate of oxide platelet precipitates is propor tional to the square root of time in 40 m Omega cm samples and (ii) the pre cipitate morphology changes from plate to polyhedral and strain around the precipitate decreases during annealing at 900 degrees C in 6, 9, and 18 m O mega cm samples. These results indicate that changes in precipitate morphol ogy occur because the oxygen precipitation and boron atom size effects are enhanced by increasing boron concentration. (C) 1999 The Electrochemical So ciety. All rights reserved.