Optimizing Hafnium Oxide Thin-Film Dielectrics: Developing a novel Atomic Layer Deposition Recipe

Abstract

High-k dielectrics permit operational voltages for thinfilm transistors (TFT) to be lowered, rendering them more effective, and energy thrifty, for printed flexible electronics, including Internet-of-Things (IoT) applications. There is a need for controlled thin-film deposition of high-k materials with fewer electronic defects to avoid excessive leakage currents (FowlerNordheim tunneling) and improve the dielectric strength. This study examines hafnium oxide-based thin-film high-k dielectrics prepared by thermal atomic layer deposition (ALD) with H2O as oxidizing agent. Several widely used deposition recipes from the past two decades are compared by investigating the film elemental composition utilizing XPS, GIXRD and ellipsometry as well as the electrical features by measuring metal oxide semiconductor structures. A new recipe is also developed following postdeposition furnace annealing to optimize the film quality and electrical characteristics.