Probing the properties of atomic layer deposited ZrO2 films on p-Germanium substrates

Zirconium oxide (ZrO2) thin films of 5 and 25 nm thickness were deposited by atomic layer deposition at 250 degrees C on p-type Ge substrates. The stoichiometry, thickness, and valence band electronic structure of the ZrO2 films were investigated by x-ray and ultraviolet photoelectron spectroscopies. For the electrical characterization, metal-oxide-semiconductor (MOS) capacitive structures (Pt/ZrO2/p-Ge) have been fabricated. Capacitance-voltage and conductance-voltage (C-V, G-V) measurements performed by ac impedance spectroscopy in the temperature range from 153 to 313 K reveal a typical MOS behaviour with moderate frequency dispersion at the accumulation region attributed to leakage currents. For the determination of the leakage currents conduction mechanisms, current density-voltage (J-V) measurements were carried out in the whole temperature range. (C) 2013 American Vacuum Society. [http://dx.doi.org/10.1116/1.4768166]