Journal of the Electrochemical Society, Vol.146, No.1, 331-335, 1999
Boron autodoping in single-wafer epitaxy of silicon at reduced pressure
Autodoping is a well-known phenomenon which occurs during silicon epitaxy;deposition over heavily doped areas. In the literature, a certain number of studies have attempted to describe autodoping mechanisms for various dopants. However, as compared to n-type dopant, boron autodoping is poorly documented and seems to behave in a different way In this work, the influence of the main process parameters on boron autodoping is studied using state-of-the-art epitaxy. The experimental results show that boron autodoping decreases with decreasing bake temperature and time and with increasing pressure. Our results clearly demonstrate that the main part of boron autodoping is due to the incorporation and diffusion of boron into the crystal during the bake, and thus at first order, the growth rate does not affect boron autodoping. An additional contribution for the autodoping is, under our conditions, suspected to result from a chamber memory effect.