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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 E_a = 0.2 eV. In particular, we obtained a trap level at φ_PF= 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).