Discontinuity of B-diffusion profiles at the interface of polycrystalline Si and single crystal Si

Abstract

Boron diffusion in polycrystalline Si-on-single crystal Si systems has been studied by secondary ion mass spectrometry. The extrapolated B-diffusion profiles in polycrystalline Si and in the single crystal Si substrate reveal a discontinuity at the polycrystalline Si-single crystal Si interface. The discontinuity in the B profiles is believed to occur due to the blockage of B-defect complexes by the interfacial oxide between polycrystalline Si and the single-crystal Si substrate, as well as the immobility of these defect complexes in single crystal Si. The B in the implant peak region above the B solid solubility limit is found to be immobile in single crystal Si during annealing due to the formation of electrically inactive B-defect complexes. In polycrystalline Si, however, our results show that the B in the peak region spreads out more rapidly than in single crystal Si possibly due to the diffusion of B-defect complexes along grain boundaries. The B-defect complexes are electrically inactive as determined by spreading resistance analysis. If the B concentration is lowered below the solid solubility limit, either by decreasing the dose or by raising the anneal temperature, no discontinuity is observed in the B profile across the polycrystalline Si-single crystal Si interface.

Effect of Crystallographic Orientation and Nanoscale Surface Morphology on Poly-Si/SiOx Contacts for Silicon Solar Cells

“…Thus, the poorer poly-Si/SiO x contact passivation on a textured surface is observed for boron-doped and not phosphorous-doped contacts. This suggests that the poor passivation of the boron-doped poly-Si/SiO x contact on a textured surface is likely related to a boron−SiO x interaction, 25,26 or a high defect density created because of emitter formation, 27 rather than only poorer SiO x /c-Si interfacial passivation of a predominantly Si(111) faceted textured surface. 10,20,21 Similar observation has also been made for the pinhole-type poly-Si/ SiO x contacts on a textured surface.…”

Complex boron redistribution kinetics in strongly doped polycrystalline‐silicon/nitrogen‐doped‐silicon thin bi‐layers

“…The profiles peak evolution is similar to a Gaussian in the NiDoS region. The curves are not very abrupt at the interface and they differ clearly to those observed in poly‐Si/mono‐Si interfaces 9,10. The B redistribution profiles in the poly‐Si region show the continuous transfer within the poly‐Si/NiDoS interface.…”

Growth of Grains Effect on Boron Diffusion in Heavily Implanted Polycrystalline silicon Thin Films

“…In the reality, the state of the dopant related to this parameter was not given in a clear and single way in the literature. The ones suggests that dopant segregate to the grain boundaries [6], [12], while the others propose the possibility of clustering even at concentrations far below the solubility limit under the supersaturation of self-interstitials [7], [13].…”