Chemical structure and electrical properties of sputtered HfO2 films on Si substrates annealed by rapid thermal annealing

The chemical structure and electrical properties of HfO2 thin film grown by rf reactive magnetron sputtering after rapid thermal annealing (RTA) were investigated. The chemical composition of HfO2 films and interfacial chemical structure of HfO2/Si in relation to the RTA process were examined by X-ray photoelectron spectroscopy. Hf 4f and O 1s core level spectra suggest that the as-deposited HfO2 film is nonstoichiometric and the peaks shift towards lower binding energy after RTA. The Hf–Si bonds at the HfO2/Si interface can be broken after RTA to form Hf–Si–O bonds. The electrical characteristics of HfO2 films were determined by capacitance–voltage (C–V) and current density–voltage (J–V) measurements. The results showed that the density of fixed charge and leakage current density of HfO2 film were decreased after the RTA process in N2 atmosphere.