In some embodiments, the present invention discloses a gate dielectric deposition process, including depositing a fluorinated hafnium oxide by an ALD process utilizing a fluorinated hafnium precursor and an oxidant. A two-step ALD deposition process can be used, including a fluorinated hafnium oxide layer deposition followed by a hafnium oxide layer deposition. Hafnium oxide can provide high dielectric constant, high density, large bandgap and good thermal stability. Fluorinated hafnium oxide can passivate interface states and bulk traps in the hafnium oxide, for example, by forming Si—F or Hf—F bonds, which can improve the reliability of the hafnium oxide gate dielectrics.