Atomic layer deposition of high-permittivity yttrium-doped HfO2 films

Yttrium-doped HfO2 films were grown by atomic layer deposition via alternating HfO2 and Y2O3 growth cycles. Precursors used were (CpMe)(2)Hf(OMe)Me or Hf(NEtMe)(4) and (CpMe)(3)Y together with ozone. The 5-8 nm thick HfO2:Y films were amorphous in as-deposited state and crystallized as high-permittivity cubic/tetragonal polymorphs upon annealing. The best combination of low leakage current of 10(-7) A/cm(2) at 1 V and high capacitance was achieved with the films grown from Hf(NEtMe)(4), with yttrium content being about 6-7 atom %. The highest permittivity values measured for these films reached 30.