A study was made of boron diffusion in nitrogen-doped amorphous silicon (a-Si) layer in original bi-layer B-doped polycrystalline silicon (poly-Si)/in-situ N-doped Si layers thin films deposited by low pressure chemical vapour deposition technique. The B diffusion in the N-doped Si layer was investigated by secondary ion mass spectrometry and Fourier transform infra-red spectroscopy analysis. A new extended diffusion model was proposed to fit the secondary ion mass spectrometry profile of the bi-layer films. This model introduces new terms which take into account the effect of N concentration on the complex diffusion phenomena of B atoms in bi-layer films. Secondary ion mass spectrometry results showed that B diffusion did not exceed one third of the N-doped Si layer thickness after annealing. The reduction of the B diffusion in the N-doped Si layer was due to the formation of complex B-N as shown by infrared absorption measurements. Electrical measurements using four-probe and Hall effect techniques showed the good conductivity of the B-doped poly-Si layer after annealing treatment.

Study of Nitrogen Effect on the Boron Diffusion during Heat Treatment in Polycrystalline Silicon/Nitrogen-Doped Silicon Thin Films. L.Saci, R.Mahamdi, F.Mansour, J.Boucher, M.Collet, E.B.Pereira, P.Temple-Boyer: Japanese Journal of Applied Physics, 2011, 50[5], 051301