Published online by Cambridge University Press: 11 February 2011
Hafnium oxide is a promising dielectric for future microelectronic applications. HfO2 thin films (10–75nm) were deposited on Pt/SiO2/Si and quartz substrates by Pulsed DC magnetron reactive sputtering. Top electrodes of Pt were formed by e-beam evaporation through an aperture mask on the HfO2/Pt/SiO2/Si samples to create MIM capacitors. Various process conditions (Ar/O2 ratio, DC power, and deposition rate) and post-deposition annealing conditions (time and temperature) were investigated. The structure of the HfO2 films was characterized by X-ray diffraction (XRD) and the roughness was measured by a profilometer. The electrical properties were characterized in terms of their relative permittivity (εr(T) and εr(f)), and leakage behavior (I-V and I-t). The electrical measurements were performed over a temperature range from –5 to 200°C. For the best samples, the relative permittivity of HfO2 was found to be ∼27 after anneal and increased by 0.027%/°C with increasing temperature over the measured temperature range. At 25°C, leakage current density was below 10-8 A/cm2 at 1 volt. The optical bandgap was measured to be 5.4eV after anneal.