The B concentration profiles in rapid thermally annealed Si and strained SiGe in situ doped epitaxial layers were measured by using secondary ion mass spectroscopy. A comparison of the SiGe samples with the Si samples, after rapid thermal annealing, revealed the occurrence of retarded B diffusivity within the strained SiGe layers. A simple empirical expression for the B retardation, which depended linearly upon the Ge concentration, was developed and incorporated into a diffusion model for dopants in heterostructures. This model accurately simulated the measured B concentration profiles over a wide range of Ge fractions (0 to 10%), B peak concentrations (2 x 1018 to 3 x 1019/cm3), and rapid thermal annealing conditions (900 to 1025C, 20 to 30s).

Measurement and Modeling of Boron Diffusion in Si and Strained Si1-xGex Epitaxial Layers during Rapid Thermal Annealing. G.H.Loechelt, G.Tam, J.W.Steele, L.K.Knoch, K.M.Klein, J.K.Watanabe, J.W.Christiansen: Journal of Applied Physics, 1993, 74[9], 5520-6