Atomic layer deposition of zirconium dioxide from zirconium tetrachloride and ozone

ZrO2 films were grown by atomic layer deposition using ZrCl4 and O-3 as precursors. The films were grown on silicon substrates in the temperature range of 220-500 degrees C. The ALD rate was monotonously decreasing from 0.085 to 0.060 nm/cycle in this temperature range towards the highest temperatures studied. The content of chlorine in the films did not exceed 0.2 at.% as measured by elastic recoil detection analysis. The content of hydrogen was 0.30 and 0.14 at.% in the films grown at 300 and 400 degrees C, respectively. Structural studies revealed the films consisting of mixtures of stable monoclinic and metastable tetragonal/cubic polymorphs of ZrO2, and dominantly metastable phases of ZrO2 below and above 300 degrees C, respectively. Permittivity of dielectric layers in Al/Ti/ZrO2/(TiN/)Si capacitors with 15-40 nm thick ZrO2 ranged between 12 and 25 at 100 kHz and the dielectric breakdown fields were in the range of 1.5-3.0 MV/cm. (C) 2015 Elsevier B.V. All rights reserved.