Effects of aluminum incorporation on hafnium oxide film using plasma immersion ion implantation

The effects of aluminum implantation on HfO2 thin films using plasma immersion ion implantation (Al– PIII samples) are investigated. X-ray photoelectron spectroscopy measurements reveal that most of the implanted aluminum atoms accumulated near the surface region of the oxide film. The greatly reduced leakage current, smaller flatband shift and steep transition from the accumulation to the depletion region in the capacitance–voltage characteristics for Al–PIII samples indicate that both bulk oxide and interface traps are significantly reduced by aluminum incorporation. Even though the aluminum concentration at the Si/HfO2 interface is very low the results indicate that trace amount of aluminum at the interface leads to significant improvements in both material and electrical characteristics of the thin HfO2 films. 2008 Elsevier Ltd. All rights reserved.