| The continuing scaling of the device dimensions for the metal oxide semiconductor field effect transistor (MOSFET), is reaching its fundamental limit. The thickness of the gate dielectric currently used, SiO2, is expected to be below 2 nm for next-generation devices. Below this thickness unacceptable leakage currents due to direct tunneling will occur. By replacing the SiO 2 gate dielectric with a material with a higher dielectric constant (K) a greater physical thickness can be realized without compromising scaling performance. Among the choices for high-K materials, ZrO2 and HfO 2 have been proposed based on predicted thermodynamic stability with Si. This study will focus on the characterization of the high-K films prepared by the oxidation of Zr and Hf metals on MgO, Si, and amorphous SiO2 substrates. Particular emphasis was placed on the evolution of the interface layer formed between the high-K dielectrics and both Si and SiO2 substrates. By use of in-situ real-time characterization techniques, spectroscopic ellipsometry (SE) and time of flight mass spectrometry of recoiled ions (TOF-MSRI), the optical properties and extent of interface formation was determined. Electrical characterization of fabricated metal-oxide-semiconductor (MOS) capacitors was performed to determine the quality of the interface as represented by the density of interface traps, Dit. Correlations between the interface reactivity and interface quality were also determined. |
