Temperature and time dependence of B and P diffusion in Si during surface oxidation

Diffusion of B and P in silicon during surface oxidation in dry O2 has been measured as a function of time and temperature. The diffusion coefficients were measured for oxidations at 900, 1000, and 1100 °C for times ranging from 5 min to 4 h. For a 30-min oxidation at 900 °C, the measured P diffusion was 15 times greater than diffusion in an inert ambient. The diffusion enhancements for B and P decreased as the temperature was increased. Increasing oxidation times at a given temperature resulted in a decrease in the diffusion enhancement. The time and temperature dependence of the interstitial component of B and P diffusion are analyzed. By using P diffusion as an interstitial monitor, the fraction of boron diffusion which occurs through the interstitial mechanism is calculated to be 0.8 at 1100 °C.