Influence of thickness and growth temperature on the properties of zirconium oxide films grown by atomic layer deposition on silicon

Abstract

ZrO 2 films of thicknesses varied in the range of 3–30 nm were atomic layer deposited from ZrI 4 and H 2O–H 2O 2 on p-Si(100) substrates. The effects of film thickness and deposition temperature on the structure and dielectric properties of ZrO 2 were investigated. At 272 and 325 °C, the growth of ZrO 2 started with the formation of the cubic polymorph and continued with the formation of the tetragonal polymorph. The ratio between the lattice parameters increased with the film thickness and growth temperature. The effective permittivity, determined from the accumulation capacitance of Hg/ZrO 2/Si capacitors, increased with the film thickness, reaching 15–17 in 25-nm-thick films. The permittivity decreased with the increasing growth temperature. The hysteresis of the capacitance–voltage curves was the narrowest for the films deposited at 325 °C, and increased towards both lower and higher deposition temperatures.