Berlin 2005 – scientific programme

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HL: Halbleiterphysik

HL 24: Bauelemente

HL 24.6: Talk

Saturday, March 5, 2005, 12:00–12:15, TU P-N229

MOSFETs with high-k dielectrics Al₂O₃ and Pr₂O₃ — •Bernhard Fabel, Michael Oswald, Martin Sterkel, and Walter Hansch — Institute for Technical Electronics, Technical University Munich, Arcisstr. 21, 80333 Munich, Germany

MOS devices were fabricated and characterized for optimisation of high-k materials properties and fabrication conditions and compared to reference MOSFETs with SiO₂ gate dielectric. In the reference MOSFETs SiO₂ (d_Ox≈25 nm) as gate dielectric and aluminium metal gate were implemented and characterized. Approving the reproducibility of these devices the SiO₂ was replaced by the promising high-k candidates aluminium oxide Al₂O₃ and praseodymium oxide Pr₂O₃. Al₂O₃ was deposited by atomic layer deposition (ALD) at 300^∘C and 1 mbar. Pr₂O₃ was evaporated in ultra high vacuum in a molecular beam epitaxy (MBE) system at room temperature. Capacitance and conductance measurements were used to extract the following MOS parameters: dielectric constant є_r, interface state density D_it, flatband voltage shift Δ V_FB. The breakthrough field E_BD could be determined by measuring the current density. MOSFETs transfer characteristics lead to the values of threshold voltage shift Δ V_Th, channel mobility µ, subthreshold swing S, I_on and I_off current. Due to the data of the reference devices, it is possible to evaluate the high-k device and material properties by comparing the extracted parameters.