At this thickness, quantum mechanical tunneling makes the leakage current unacceptable. Metal oxides such as zirconium oxide are therefore considered to replace SiO 2 .
Zirconium oxide is relatively stable on silicon surface and has a high dielectric constant.
Thus a new etching process has to be developed before we can integrate zirconium oxide as the gate dielectric material. Our project is to study the kinetics of etching zirconium oxide using chlorine gas in a high-density plasma reactor. In most chemical reactions, the reaction rate is a function of the reactant concentration, so does the plasma etching reaction. In the case of plasma etching, the concentration of free radicals and the chemical nature of the etching products are also very important. If a nonvolatile product is produced on the thin film surface, the mass transfer of reacting species to the reaction sites will be slowed down and eventually the etching process will be stopped.