Influence of carbon incorporation on dopant surface segregation in molecular-beam epitaxial growth of silicon

We describe the effect of carbon incorporation into Si on dopant surface se gregation during molecular-beam epitaxial growth. Low concentration of carb on can significantly reduce the surface segregation of boron and phosphorus . Combining the surface diffusion model with a two-state exchange process, we are able to model the experimental results over the whole temperature ra nge between 350 and 800 degrees C. Each exchange process alone is not suffi cient to describe surface segregation at all investigated temperatures. Our results show that the presence of carbon lowers the energy difference for boron in subsurface and surface states. The energy barriers for surface dif fusion as well as for the two-state exchange process are not affected by ca rbon. (C) 2000 American Institute of Physics. [S0003- 6951(00)02339-1].