High-κ Lanthanum Zirconium Oxide Thin Film Dielectrics from Aqueous Solution Precursors

Abstract

Metal oxide thin films are critical components in modern electronic applications. In particular, high-κ dielectrics are of interest for reducing power consumption in metal-insulator-semiconductor (MIS) field-effect transistors. Although thin-film materials are typically produced via vacuum-based methods, solution deposition offers a scalable and cost-efficient alternative. We report an all-inorganic aqueous solution route to amorphous lanthanum zirconium oxide (LaZrO, LZO) dielectric thin films. LZO films were spin-cast from aqueous solutions of metal nitrates and annealed at temperatures between 300 and 600 °C to produce dense, defect-free, and smooth films with subnanometer roughness. Dielectric constants of 12.2-16.4 and loss tangents <0.6% were obtained for MIS devices utilizing LZO as the dielectric layer (1 kHz). Leakage currents <10 A cm at 4 MV cm were measured for samples annealed at 600 °C. The excellent surface morphology, high dielectric constants, and low leakage current densities makes these LZO dielectrics promising candidates for thin-film transistor devices.

Toward Thick Piezoelectric HfO2‐Based Films

“…Figure b compares experimental pattern with a simulated one for a density of 9.6 g cm − 2 , as expected for a monoclinic phase with 5 cat% of La. Such lower densities appear to be a common issue for CSD of HfO 2 and ZrO 2 judging from SEM, transmission electron microscopy, or atomic force microscopy images and from fewer cases of reported XRR results …”

Nontoxic, Eco‐friendly Fully Water‐Induced Ternary Zr–Gd–O Dielectric for High‐Performance Transistors and Unipolar Inverters

“…Meanwhile, some solution‐derived Zr‐based TFTs have been fabricated and some optimized performance has been detected . Although there exists some investigations on the solution‐processed ZrO 2 ‐based TFTs, common solution routes rely on organic additives and solvents which must be expelled during film processing, leading to porosity and undesirable high leakage currents in devices . Many of these disadvantages can be circumvented by using aqueous precursors.…”

Application of Amorphous Zirconium-Yttrium-Aluminum-Magnesium-Oxide Thin Film with a High Relative Dielectric Constant Prepared by Spin-Coating

“…The oxides applied to the insulating layer have been a single-metal or binary-metal system so far, for example, AlO x [ 19 , 20 ], HfO x [ 21 ], YO x [ 9 , 22 ], AlZrO x [ 23 , 24 ], YAlO x [ 25 ], LaZrO x [ 26 ], ZnMgO x [ 27 ], etc. However, most of them can only make one breakthrough in the band gap, leakage current or permittivity.…”