Deposition of Lanthanum Zirconium Oxide High‐k Films by Liquid Injection ALD and MOCVD

Thin films of lanthanum zirconium oxide, LaxZr1–xO2–δ (x = 0.09 – 0.77) are deposited by liquid injection metal‐organic (MO)CVD and atomic layer deposition (ALD) using toluene solutions of the precursors [(iPrCp)3La] and [(MeCp)2ZrMe(OMe)]. Auger electron spectroscopy (AES) shows that LaxZr1–xO2–δ films grown by ALD at 300 °C contain carbon at levels of 3.2 – 5.4 at.‐ %, whilst films grown by MOCVD at 400 °C contain carbon levels of 2.4 – 10.5 at.‐ %. Analysis by X‐ray diffraction (XRD) shows that films with lower La contents (x) of 0.09 and 0.22 crystallize into cubic lanthanum‐stabilized zirconia phase on annealing at 700 °C, whereas films of higher La content (x = 0.35, 0.63) remain amorphous. In general, the onset of crystallization of these films increases with the lanthanum fraction. For x = 0.35, crystallization to the cubic phase of ZrO2 is observed between 800 and 900 °C. LaxZr1–xO2–δ films grown by ALD show good dielectric properties with low hysteresis voltages, negligible flatband voltage shifts, and k values ranging from 11 to 14. LaxZr1–xO2–δ films grown by ALD have leakage current densities of 2.6 × 10–6 – 5.3 × 10–7 A cm–2, while films grown by MOCVD have leakage current densities of between 1.1 × 10–6 A cm–2 and 8.3 × 10–7 A cm–2.