Berlin 2008 – wissenschaftliches Programm
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DF: Fachverband Dielektrische Festkörper
DF 13: Dielectric and ferroelectric thin films and nanostructures III
DF 13.1: Vortrag
Donnerstag, 28. Februar 2008, 14:00–14:20, EB 107
Current transport mechanism in metal/HfO2/metal structures — •christian walczyk1, thomas schroeder1, christian wenger1, jaroslaw dabrowski1, mindaugas lukosius1, sergej pasko2, and christoph lohe2 — 1IHP, Im Technologiepark 25, 15236 Frankfurt (Oder), Germany. — 2AIXTRON AG, Kackertstr. 15-17, 52072 Aachen, Germany.
The metal-insulator-metal (MIM) capacitor integration into BiCMOS technology is governed by the efforts toward increasing the capacitance density, reducing the leakage current density and improving the voltage linearity. In particular, achievement of an acceptable leakage current density in BEOL MIM capacitors is still a challenge. To get around this critical problem, high-k dielectrics have been introduced. Among various candidates, HfO2 has been investigated due to its high dielectric constant, low leakage current and chemical stability 1. Despite the considerable efforts for HfO2, its current transport mechanism in MIM structures needs further investigations. Based on experimental results of the temperature dependence of the leakage current, we studied the current transport mechanism and energy band diagrams. The leakage current was measured in the temperature range of 200 - 400 K. The slope of an Arrhenius plot yielded activation energies in the range of Ea = 0.2 eV. In particular, we obtained a trap level at φPF= 0.4 eV below the HfO2 conduction band which contributes to Poole-Frenkel conduction.
[1] M. Houssa et al., Materials Science and Engineering R51, (2006).