Non-contact monitoring of Ge and B diffusion in B-doped epitaxial Si _1-xGe_x bi-layers on silicon substrates during rapid thermal annealing by multiwavelength Raman spectroscopy

B-doped, thin Si_1-xGe_x bi-layers with different Ge content and B concentrations were epitaxially grown on Si(100) device wafers. Diffusion behavior of Ge and B atoms during rapid thermal annealing were monitored by multiwavelength micro-Raman spectroscopy. Raman spectra indicating possible Ge and B redistribution by thermal diffusion was observed from B-doped, thin Si_1-xGe_x bi-layers on Si(100) wafers after rapid thermal annealing at 950°C or higher. Significant Ge and B diffusion in Si_1-xGe_x bi-layers and Si substrates was verified by secondary ion mass spectroscopy. Pile up of B atoms at the surface and at the boundary between Si_1-xGe_x bi-layers was observed in the early stages of thermal diffusion.