Praseodymium compound formation in silicon by ion beam synthesis

Abstract The compound formation in the ternary system Pr–Si–O initiated by ion beam synthesis inside bulk-Si was studied by transmission electron microscopy and X-ray diffraction. The oxygen content was varied by additional O + ion implantation and by oxidation of the bulk-Si. For annealing temperatures of 1100 °C, Pr silicate nanoclusters were observed consisting of Pr 9.33 Si 6 O 26 or Pr 2 Si 2 O 7 . These silicates were the dominating and most stable Pr compounds. The interfaces between Pr silicate and the crystalline Si were atomically abrupt after high-temperature annealing. Pr silicide (PrSi 2 ) was detected for lower annealing temperatures such as 900 °C and for higher annealing temperatures in minor fraction also in samples with enhanced O content. Pr oxide (Pr 2 O 3 ), the promising high- k material, was not definitely verified. In ion beam synthesis, the energy related to structural reordering during solid-state compound formation is a parameter that controls the proceeding processes in addition to other parameters like chemical reactivity and the compound interface matching.