Role of a Si0.95Ge0.05 epilayer cap on boron diffusion in silicon under inert and dry oxidizing ambient annealing

Silicon (Si) and Si with a 60 nm Si0.95Ge0.05 epilayer cap (Si0.95Ge0.05/Si) were implanted with 60 keV, 1×1013 cm−2 boron (B) followed by annealing in nitrogen (N2) or dry oxygen (O2) in two different anneal conditions. B+implantation energy and dose were set such that the B peak is placed inside Si in Si0.95Ge0.05/Si samples and concentration independent B diffusion is achieved upon annealing. For samples annealed above 1075 °C, Ge diffusing from the Si0.95Ge0.05 epilayer cap in Si0.95Ge0.05/Si samples reached the B layer inside Si and resulted in retarded B diffusion compared to the Si samples. For annealing done at lower temperatures, diffusion of Ge from Si0.95Ge0.05 epilayer cap does not reach the B layer inside Si. Thus B diffusion profiles in the Si and Si0.95Ge0.05/Si samples appear to be similar. B diffusion in dry oxidizing ambient annealing of Si0.95Ge0.05/Si samples further depends on the nature of Si0.95Ge0.05 oxidation which is set by the duration and the thermal budget of the oxidizing anneal.