Atomic layer deposition of HfO sub(2) thin films and nanolayered HfO sub(2)-Al sub(2)O sub(3)-Nb sub(2)O sub(5) 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 degree 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 degree 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.