Atomic Layer Deposition of ZrO2 thin films Using CpZrNMe23 and Water

Abstract

Zirconia (ZrO2) is a dielectric with relatively wide band gap (7.8 eV), high refractive index and high dielectric constant (17-25), high breakdown field (7-15 MV/cm). These properties make ZrO2 very attractive for the optical and electronic applications. Various methods have been proposed for the formation of ZrO2 such as sputtering and chemical vapor deposition methods. Recently, in view of film uniformity, thickness control capability in the small thickness region, and low impurity, the application of atomic layer deposition (ALD) is accelerating with apparently significant benefits in the fabrication of various dielectrics. One of the most commonly studied ZrO2 ALD methods is the ZrCl4 with H2O process, which has several disadvantages such as high evaporation temperature of the precursor, residue chlorine impurity of the films and generation of HCl as a by-product. For these reasons, it is important to find a Zr precursor that can replace ZrCl4. In this study, we demonstrated the ZrO2 ALD process based on tris(dimethylamino)cyclopentadienylzirconium CpZr(NMe2)3 and H2O. At a growth temperature of 300℃, we have obtained tetragonal ALD ZrO2 conformal films with proper growth rate and low impurity concentrations.