Detailed leakage current analysis of metal–insulator–metal capacitors with ZrO2, ZrO2/SiO2/ZrO2, and ZrO2/Al2O3/ZrO2 as dielectric and TiN electrodes

Abstract

ZrO2-based metal–insulator–metal capacitors are used in various volatile and nonvolatile memory devices as well as for buffer capacitors or radio frequency applications. Thus, process optimization and material tuning by doping is necessary to selectively optimize the electrical performance. The most common process for dielectric fabrication is atomic layer deposition which guarantees high conformity in three dimensional structures and excellent composition control. In this paper, the C–V and J–V characteristics of ZrO2 metal–insulator–metal capacitors with TiN electrodes are analyzed in dependence on the O3 pulse time revealing the optimum atomic layer deposition process conditions. Moreover, a detailed study of the leakage current mechanisms in undoped ZrO2 compared to SiO2- or Al2O3-doped ZrO2 is enclosed. Thereby, the discovered dependencies on interfaces, doping, layer thickness, and crystalline phase's enable the detailed understanding and evaluation of the most suitable material stack for dynamic random access memory devices below the 20 nm generation.