Peer-Reviewed Journal Details
Mandatory Fields
Cherkaoui, K;Monaghan, S;Negara, MA;Modreanu, M;Hurley, PK;O'Connell, D;McDonnell, S;Hughes, G;Wright, S;Barklie, RC;Bailey, P;Noakes, TCQ
2008
September
Journal of Applied Physics
Electrical, structural, and chemical properties of HfO(2) films formed by electron beam evaporation
Published
45 ()
Optional Fields
GATE DIELECTRICS HAFNIUM OXIDE INTERFACE SILICON DEFECTS DEPOSITION LAYER SI TRANSISTORS THICKNESS
104
High dielectric constant hafnium oxide films were formed by electron beam (e-beam) evaporation on HF last terminated silicon (100) wafers. We report on the influence of low energy argon plasma (similar to 70 eV) and oxygen flow rate on the electrical, chemical, and structural properties of metal-insulator-silicon structures incorporating these e-beam deposited HfO(2) films. The use of the film-densifying low energy argon plasma during the deposition results in an increase in the equivalent oxide thickness (EOT) values. We employ high resolution transmission electron microscopy (HRTEM), x-ray photoelectron spectroscopy (XPS), and medium energy ion scattering experiments to investigate and understand the mechanisms leading to the EOT increase. We demonstrate very good agreement between the interfacial silicon oxide thicknesses derived independently from XPS and HRTEM measurements. We find that the e-beam evaporation technique enabled us to control the SiO(x) interfacial layer thickness down to similar to 6 angstrom. Very low leakage current density (< 10(-4) A/cm(2)) is measured at flatband voltage +1 V into accumulation for an estimated EOT of 10.9 +/- 0.1 angstrom. Based on a combined HRTEM and capacitance-voltage (CV) analysis, employing a quantum-mechanical CV fitting procedure, we determine the dielectric constant (k) of HfO(2) films, and associated interfacial SiO(x) layers, formed under various processing conditions. The k values are found to be 21.2 for HfO(2) and 6.3 for the thinnest (similar to 6 angstrom) SiO(x) interfacial layer. The cross-wafer variations in the physical and electrical properties of the HfO(2) films are presented. (c) 2008 American Institute of Physics. [DOI: 10.1063/1.2978209]
MELVILLE
0021-8979
10.1063/1.2978209
Grant Details