Tunable high-κ ZrxAl1−xOy thin film dielectrics from all-inorganic aqueous precursor solutions

Abstract

Zirconium oxide has received considerable attention as a dielectric component for microelectronic applications. However, crystallization at relatively low temperatures results in the formation of grain boundaries and high leakage current densities. Doping ZrO_y with Al is known to suppress crystallization, but the effects of Al incorporation on dielectric properties has not been investigated over the complete range of Zr : Al compositions in Zr_xAl_1−xO_y (ZAO). Herein, we report an aqueous, all-inorganic route to amorphous high-κ ZAO thin film dielectrics with varying Zr : Al composition. ZAO thin films were spin-cast and annealed at temperatures between 200 and 600 °C to produce dense, uniform, and smooth films with sub-nm roughness. In general, Zr-rich films had higher dielectric constants, ranging from 18.6 for pure ZrO_y to 5.4 for pure AlO_y (1 kHz), while Al-rich films had lower leakage current densities. Of the compositions studied, Zr_0.75Al_0.25O_y films displayed the optimal balance of dielectric properties and low leakage current densities, making them promising candidates for microelectronic devices.