Evidence of recombination enhanced diffusion of impurities at low temperature into high-k dielectric with tantalum oxide as an example

For ordinary diffusion of Si into Ta2O5 on a Si substrate, there should be no difference for n-type or p-type substrate; however, experimentally, we noticed that Si can diffuse rapidly and this diffusion process tended to be faster for n-type Si substrate than for p-type Si substrate under an oxygen plasma at 350 °C. This can only be explained by the mechanism of recombination enhanced diffusion. Beside Si, B, and Sb were shown to be able to diffuse into tantalum oxide under an oxygen plasma or nitrous oxide plasma at a temperature below 400 °C.