Atomic layer deposition of HfO2 thin films and nanolayered HfO2-Al2O3-Nb2O5 dielectrics

Smooth, 4-6-nm thick hafnium oxide films were grown by atomic layer deposition from HfI^sub 4^ or HfCl^sub 4^ and H^sub 2^O on SiO^sub 2^/Si(1 0 0) substrates at 300 °C. Non-uniform films were obtained on hydrogen-terminated Si(1 0 0). The stoichiometry of the films corresponded to that of HfO^sub 2^. The films contained small amounts of residual chlorine and iodine. The films deposited on SiO^sub 2^/Si(1 0 0) were amorphous, but crystallized upon annealing at 1000 °C. In order to decrease the conductivity, the HfO^sub 2^ films were mixed with Al^sub 2^O^sub 3^, and to increase the capacitance, the films were mixed with Nb^sub 2^O^sub 5^. The capacitance-voltage curves of the Hf-Al-O mixture films showed hysteresis. The capacitance-voltage curves of HfO^sub 2^ films and mixtures of Hf-Al-Nb-O were hysteresis free.[PUBLICATION ABSTRACT]