Interface characterization and carrier transportation in metal/HfO2/silicon structure

Metal-oxide-semiconductor capacitors incorporating HfO2 dielectrics were fabricated and investigated. In this work, the structural and electrical characterizations were performed at the interfaces of HfO2/Si and Al/HfO2, respectively. The physical analyses reveal that an interfacial layer of Hf-silicate between 700 degrees C-annealed HfO2 and Si was formed. The dominant conduction mechanisms of the Al/HfO2/p-Si structure are the Schottky emission at high temperatures (greater than or similar to 465 K) and low electric fields (less than or similar to 2.2 MV/cm) and the Fowler-Nordheim tunneling at low temperature (77 K) and high electric fields (greater than or similar to 2.6 MV/cm), respectively. The electron effective mass in HfO2 and the barrier height at the Al/HfO2 interface are evaluated using both the intercept of the Schottky plot and the slope of the Fowler-Nordheim plot. Therefore, the barrier height at the Al/HfO2 interface was determined to be about 0.94 eV. The electron effective masses in HfO2 are 0.4m(0) and 0.09m(0) for the effective oxide thickness (EOT)=6 nm and EOT=3.15 nm, respectively. (c) 2006 American Institute of Physics.