Deposition temperature effect on electrical properties and interface of high-k ZrO2 capacitor

• Published in: Journal of physics. D, Applied physics Applied physics, 2008-09, Vol.41 (17), p.172005-172005 (6)
• Main Authors: Kim, Joo-Hyung, Ignatova, Velislava A, Heitmann, Johannes, Oberbeck, Lars
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Dielectric properties of solids and liquids; Dielectrics, piezoelectrics, and ferroelectrics and their properties; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronic transport in interface structures; Exact sciences and technology; Metal-nonmetal contacts; Permittivity (dielectric function); Physics
• ISSN: 0022-3727; 1361-6463
• DOI: 10.1088/0022-3727/41/17/172005

The electrical characteristics, i.e. leakage current and capacitance, of ZrO2 based metal-insulator-metal structures, grown at 225, 250 and 275 deg C by atomic layer deposition, were studied. The lowest leakage current was obtained at 250 deg C deposition temperature, while the highest dielectric constant (k ~ 43) was measured for the samples grown at 275 deg C, most probably due to the formation of tetragonal/cubic phases in the ZrO2 layer. We have shown that the main leakage current of these ZrO2 capacitors is governed by the Poole-Frenkel conduction mechanism. It was observed by x-ray photoelectron spectroscopy depth profiling that at 275 deg C deposition temperature the oxygen content at and beyond the ZrO2/TiN interface is higher than at lower deposition temperatures, most probably due to oxygen inter-diffusion towards the electrode layer, forming a mixed TiN-TiOxNy interface layer. At and above 275 deg C the ZrO2 layer changes its structure and becomes crystalline as proven by XRD analysis.