The Metal-Organic Chemical Vapor Deposition of Lanthanum Nickelate Electrodes for Use in Ferroelectric Devices

Lanthanum nickelate layers have been deposited onto 100 mm diameter silicon/silicon dioxide and (0001) sapphire substrates by liquid‐delivery metal–organic (MO) CVD using the precursors La(thd)3 and Ni(thd)2 (thd = 2,2,6,6‐tetramethyl‐3,5‐heptanedionato) dissolved in tetrahydrofuran and heptane. The LaNiO3 (LNO) was deposited at 630 °C in an oxidizing atmosphere, and the as‐grown layers were highly crystalline and highly (110)‐oriented on Si/SiO2. Electrical resistivity studies were performed and showed a dependence on the La/Ni ratio, the substrate used, and the post‐deposition annealing conditions. A minimum electrical resistivity value of 300 μΩ cm was measured for LNO deposited on (0001) sapphire and rapidly annealed at 750 °C. The resistivity values of the LNO layers deposited onto silicon/silicon dioxide were higher, with a minimum value of 1 mΩ cm. The rapid annealing at 750 °C resulted in cracking of some of the LNO layers deposited onto the silicon substrates. However, the layers that were nickel‐rich withstood the annealing treatment better and showed little evidence of cracking. Lanthanum nickelate (LNO) films are deposited on Si/SiO2 and sapphire substrates at 630 °C by liquid delivery MOCVD using La(thd)3 and Ni(thd)2 (thd = 2,2,6,6‐tetramethyl‐3,5‐heptadionato) dissolved in tetrahydrofuran and heptane. The as grown layers are highly crystalline (see Figure) and highly oriented on Si/SiO2 substrates. Electrical resistivity is found to be dependent on La:Ni ratio, substrate and annealing conditions with a minimum value of 300 μΩ cm for LNO on (0001) sapphire.