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Low pressure chemical vapour deposition of heavily boron doped polycrystalline silicon thin films: preparation and characterizations

Heavily boron
- doped polycrystalline silicon samples were prepared by horizontal low pressure chemical vapour deposition (LPCVD) at 750 °C. The as-deposited samples were thermally annealed at 1200 °C in diffusion furnace filled with water vapour and, thereafter, HF etched. The sheet resistance was determined by four point probe method. The low temperature resistivity measurements were made from room temperature down to 2K. The observed resistivity drop at the lowest temperatures was discussed within Altshuler’ s theory for the two dimensional disordered metals conduction models. The Fano-type interference on transversal optical (TO) vibrational modes was observed in the Raman spectra. The boron concentration embedded in bulk silicon grains was estimated from the asymmetry and the shift of the TO phonon mode.

polysilicon; LPCVD; boron concentration; sheet resistance; Raman spectroscopy;

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