Dielectric properties investigation of a compound based on atomic layer deposited multi-layer structure

Abstract

This study presents dielectric properties investigation of hafnium oxide (HfOx), aluminum oxide (AlOx) and tantalum oxide (TaOx) thin films and HfAlTaOx compound based on their multilayer structure. The thickness of all films under study was 40 nm. The investigated films were produced from metal-organic precursors by Plasma Enhanced Atomic Layer Deposition (PEALD). Based on the dielectrics mentioned above, we produced Metal – Insulator – Metal (MIM) capacitors and researched their properties. Dielectric constant for HfOx, AlOx, TaOx and HfAlTaOx was 20, 9, 31 and 13, correspondingly. Volumetric efficiency of MIM capacitors based on HfOx, AlOx, TaOx and HfAlTaOx was 4.4 nF/mm2, 2 nF/mm2, 6.8 nF/mm2 and 2.9 nF/mm2, correspondingly. Dielectric strength of HfAlTaOx compound was significantly higher (8.2 MV/cm) compared to other dielectrics: HfOx (3.6 MV/cm), AlOx (6.4 MV/cm), TaOx (1.5 MV/cm). The greatest values were observed in the compound of significantly higher dielectric strength which is comparable to silicon oxide. This study was the first to demonstrate the advantages of the produced compound, such as high dielectric constant and dielectric strength.