Investigation of zirconium oxide based high-k dielectrics for future memory applications

Abstract

Zirconium oxide based high-k dielectrics are studied for their possible future integration in Dynamic Random Access Memory (DRAM) Metal-Insulator-Metal (MIM) capacitors. To better understand their electrical properties a combined study is presented considering both their macroscopic and mesoscopic electrical behavior. Molecular beam deposition is used to deposit thin films of ZrO2 as well as (ZrO2) x(Al2O3)1−x. Three different ZrO2 deposition methods are compared and evaluated by capacitance voltage (CV) and current voltage (IV) measurements. These deliver valuable information for benchmarking. To further understand the leakage current mechanism in nanometer thin zirconate based films conductive atomic force microscopy is performed. IV curves are taken with high spatial resolution enabling a detailed comparison between the leakage paths at crystallites and in the amorphous matrix. Through this method the evolution of the leakage path formation can be traced.