Interface effect on dielectric constant of HfO2/Al 2O3 nanolaminate films deposited by plasma-enhanced atomic layer deposition

Abstract

The effect of the interface between Al2O3 and HfO2 sublayers on the dielectric constant was investigated in HfO2/Al2O3 nanolaminate films deposited using plasma-enhanced atomic layer deposition. After annealing at 700 degrees C, the dielectric constants of the nanolaminate films with a sublayer thickness of 40 A or greater were the same as the calculated values for a series of capacitors consisting of amorphous Al2O3 and monoclinic or tetragonal HfO2. As the sublayer thickness was reduced to 10 A, the dielectric constant increased up to 17.7 because a thin Hf-O-Al mixture layer, of which the number increases drastically in the nanolaminate films with thin sublayers, is formed at the interface. (c) 2007 American Institute of Physics.