Dopant Diffusion during Amorphous Silicon Crystallization
We have investigated the redistribution of B during the crystallization of an amorphous Si layer homogeneously doped with P. The redistribution of B only occurs for concentrations lower than 2 × 1020 at cm−3. Crystallization leads to a non “Fickian” redistribution, allowing an abrupt interface between the regions doped and undoped with B. Once the crystallization is ended, B diffuses through the layer in the type B regime with a coefficient which is in agreement with the literature data for diffusion in polycrystalline Si. Although the P distribution is homogeneous in the entire layer, for a temperature as high as 755 °C, P diffuses towards the region the most concentrated in B. The B and P interactions are interpreted as chemical interactions.
D. L. Beke, Z. Erdélyi and I. A. Szabó
A. Portavoce et al., "Dopant Diffusion during Amorphous Silicon Crystallization", Defect and Diffusion Forum, Vol. 264, pp. 33-38, 2007