Physical properties and electrical characteristics of H2O-based and O3-based HfO2 films deposited by ALD

Ozone (O3) and H2O are used as the oxidant to deposit hafnium oxide (HfO2) thin films on p-type Si (1 0 0) wafers by atomic layer deposition (ALD). The physical properties and electrical characteristics of HfO2 films change greatly for different oxidants and deposition temperature. Compared with O3 as the oxidant, HfO2 films grown with H2O as the oxidant are more consistent in composition and growth rate. The O3-based HfO2 films have lower C impurity and higher concentration N impurity than the H2O-based HfO2 films. The impact of the annealing process on the electrical properties and stability of HfO2 films are also investigated. A width step is observed in the O3-based HfO2 C–V curves, which disappears after annealing process. It is because the unstable Hf–O–N and Hf–N bonds in O3-based HfO2 films are re-bonded with the non-HfO2 oxygen after annealing process, and the binding energy of N1s shifts.