Redistribution of implanted species in polycrystalline silicon films on silicon substrate

Redistributions of implanted species after thermal annealing in polycrystalline silicon (poly-silicon) were studied by secondary ion mass spectrometry. Ten different elements were implanted into poly-silicon films grown on Si substrates. The implanted energies were chosen such that the expected ion range is within the poly-silicon film. Thermal anneals were carried out at temperatures between 300 degrees C and 1000 degrees C in flowing high purity Ar gas. Three different diffusion behaviors have been observed for these elements. For Be, Na, Ga, and Cr, most of the implanted ions diffused out to the surface of the poly-silicon film after anneal at 1000 degrees C. For K, Ca, Ti, and Ge, the impurity ions diffused deeper into the bulk after anneal at 1000 degrees C. For Cl and Mn ions, the concentration distributions became narrower when annealed at high temperatures.