Solubility and Diffusion Coefficient of Oxygen in Silicon

Abstract

The solubility and diffusion coefficient of oxygen in silicon between 1000°C and 1375°C were examined by charged particle activation analysis with the¹⁶O(³He, p)¹⁸F reaction, in which oxygen was activated with an equal probability over the depth of up to 250 µm by a specially devised apparatus. Silicon wafers of known histories were heated in oxygen or argon for 12 to 473 hours, and the resultant oxygen depth profiles were determined by the activation, subsequent stepwise etching and¹⁸F activity measurement. The solubility thus obtained is given as 9.3×10²¹exp [-27.6 kcal mol^-1/RT] at·cm^-3; the diffusion coefficient has been found to be approximated as 3.2 exp [-67.1 kcal mol^-1/RT] cm²s^-1over 1150°C, under which the apparent activation energy seems to decrease with decrease of temperature.