The effect of post-deposition annealing on the chemical, structural and electrical properties of Al/ZrO₂/La₂O₃/ZrO₂/Al high-k nanolaminated MIM capacitors

The metal-insulator-metal (MIM) is being used as the potential device in the research interest of modern materials for nanoelectronics applications in semiconductor industries. In this context, the chemical, structural and electrical properties of plasma-enhance atomic layer deposition (PEALD) deposited ZrO₂/La₂O₃/ZrO₂ (ZLZ) nanolaminates at low substrate temperature have been studied and compared with, 300 °C, 400 °C, and 500 °C annealed ZLZ nanolaminates. The Tetrakis-(ethylmethylamido) zirconium-IV and Tris-(cyclopentadienyl) lanthanum-III were used as precursors for the zirconium and lanthanum whereas, O₂ plasma was utilized as the oxidizing agent in each PEALD cycle. Root-mean-square (RMS) surface roughness was determined using atomic force microscopy. The x-ray photoelectron spectroscopy and x-ray diffraction measurements were used to investigate the effect of post-deposition annealing on the phase change of ZLZ nanolaminates. The film annealed at 400 °C in an atmospheric environment gives the stable phase formation of the pyrochlore phase of La₂Zr₂O₇. This stable phase formation of 400 °C annealed Al/ZLZ/Al MIM capacitor provides the lowest leakage current density of 6.20 × 10^{− 7} A/cm² at 1 V compared to the as-deposited films. The barrier height of 0.42 eV for this MIM capacitor was extracted from the Fowler-Northeim (FN) tunneling model. The obtained results of PEALD nanolaminated high-k MIM capacitors having a controlled phase indicate the potential use for nanoelectronics applications.