ABRUPT BORON PROFILES BY SILICON-MBE

Surface segregation and diffusion are the dominant mechanisms for profile smearing. However in the low temperature regime below 600°C diffusion is negligible. We investigated the dopant profile during silicon molecular beam epitaxy (MBE) in silicon (100). A method for measurement of the adlayer density of segregating dopant atoms is suggested. We utilize the results of this experiment to generate very sharp boron profiles. For the doping we use the pre-build up method with constant boron flux.