AVS 60th International Symposium and Exhibition
    Thin Film Thursday Sessions
       Session TF-ThP

Paper TF-ThP10
Fabrication and Electrical Properties of Nanocrystalline Yttrium-Doped Hafnium Oxide Thin Film Capacitors

Thursday, October 31, 2013, 6:00 pm, Room Hall B

Session: Thin Films Poster Session
Presenter: A. Kongu, University of Texas at El Paso
Authors: A. Kongu, University of Texas at El Paso
S. McPeak, The University of Alabama
S. Kotru, The University of Alabama
C.V. Ramana, University of Texas at El Paso
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Hafnium oxide (HfO2) has emerged as the most promising high-k dielectric for Metal-Oxide-Semiconductor (MOS) devices and has been highlighted as the most suitable dielectric materials to replace silicon oxide because of its comprehensive performance. In the present research, yttrium-doped HfO2 (YDH) thin films were fabricated using RF magnetron sputter deposition onto Si (100) with a variable thickness. Electrical properties such as capacitance-voltage (C-V), current-voltage (I-V), leakage and breakdown characteristics of YDH films were studied. YDH films that were relatively thin (<1500 A°) crystallized in monoclinic phase while thick films crystallized in cubic phase. The band gap (Eg) of the films was calculated from the optical measurements using linear regression. The band gap was found to be ~5.60 eV for monoclinic YDH films while it is ~6.05 eV for cubic. Cross-sectional SEM and Filmetrics were used to measure the thickness of the films. The thicknesses of the films range from 700 A° to 7500 A°. Frequency dependence of the electrical resistivity (ρac) and the total conductivity of the films were measured. Resistivity decreased (by three orders of magnitude) with increasing frequency from 100 Hz to 1 MHz, attributed due to the hopping mechanism in YDH films. Whereas, while ρac~1 Ω-m at low frequencies (100 Hz), it decreased to ~ E-4 Ω-cm at higher frequencies (1 MHz). Aluminum electrodes were deposited to fabricate a thin film capacitor with YDH layer as dielectric film thereby employing Al–YDH–Si capacitor structure. The results indicate that the capacitance of the films decrease with increasing film thickness. A detailed analysis of the electrical characteristics of YDH films is presented.