Dresden 2009 – wissenschaftliches Programm

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DF: Fachverband Dielektrische Festkörper

DF 5: High-k and low-k Dielectrics

DF 5.5: Vortrag

Montag, 23. März 2009, 16:20–16:40, WIL B321

High performance MIM capacitors with Atomic Vapour Deposited HfO₂ dielectrics — •Mindaugas Lukosius, Christian Wenger, Christian Walczyk, and Hans-Joachim Müssig — IHP, Im Technologiepark 25, 15236 Frankfurt (Oder), Germany

Metal-Insulator-Metal (MIM) capacitors are widely used in ICs for Radio-Frequency (RF) applications. Currently, capacitors fabricated by performing MIM structures use silicon oxide or silicon nitride as an insulating layer. However the capacitance density of these materials is limited by low dielectric constant values. Therefore, for further integration of passive components such as capacitors into CMOS devices, dielectric materials with higher permittivity than SiO₂ (k = 3.9) are required. Using the high dielectric constant (high-k) material HfO₂ as a dielectric in MIM capacitor seems to be a very promising approach. Atomic Vapour Deposition (AVD*) technique was used for the preparation of hafnium oxide films on 20nm TiN/2nmSiO₂/Si (200mm) substrates using Hf(NEtMe)₄ precursor for MIM applications in back-end of line (BEOL). The influence of process temperature (320 - 425 ^∘C) and process pressure (2-10mbar) on the structural and electrical properties of HfO₂ were investigated. The optimized dielectric layers obtained at 320 ^∘C and 4 mbar possess k value of 18, capacitance density of 3.5 fF/µm² combined with required capacitance voltage linearity (<100 ppm/V²) and quality factor of 50. Films with thickness of 35 nm exhibit leakage current density of 2·10⁻⁷ A/cm² and breakdown strength of 5.8 MV/cm, therefore AVD* deposited HfO₂ layers are possible alternative dielectric candidates for MIM applications.