Carboxylic acids as oxygen supplying agents for atomic layer deposition of high-K thin films

Atomic layer deposition (ALD) is known to be a good candidate for the growth of high-κ thin films for microelectronic applications. Contrary to standard methods, in this work no common oxygen source such as water, oxygen or ozone is used. Titania and hafnia thin films were deposited on Si(100) and Si(111) substrates using metal alkoxides and carboxylic acids as oxygen source at temperatures ranging from 50 to 350°C. The asdeposited films demonstrate good permittivity (κ) and low leakage current densities due to their purity and amorphous character. Nevertheless, post deposition annealing under nitrogen leads to a densification of the films and further improves the electrical properties. An interesting aspect of the present approach is that the applied chemical approach which was adapted from non-aqueous sol-gel chemistry has the potential to grow oxides on silicon whilst minimizing the formation of a 1ow-k interfacial layer.