Dresden 2009 – scientific programme
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DS: Fachverband Dünne Schichten
DS 8: High-k and low-k dielectrics
DS 8.5: Talk
Monday, March 23, 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.