High frequency characterization and continuum modeling of ultrathin high-k (ZrO2) gate dielectrics on strained-Si

Ultrathin (< 10 nm) zirconium oxide (ZrO2) films have been deposited at low temperature (150 °C) on strained-Si on relaxed-Si0.8Ge0.2 substrates by microwave plasma enhanced chemical vapor deposition (PECVD). Interfacial and electrical properties of Al/ZrO2/strained-Si MOS capacitors have been characterized using capacitance–voltage (C–V) and conductance–voltage (G–V) techniques. It is observed that Dit ranges from 4.93 × 1012 eV− 1 cm− 2 in (EC − 0.35) eV to 1.86 × 1012 eV− 1 cm− 2 in (EC − 0.82) eV and decays slowly while the time constant (τ) ranges from 3.05 × 10− 6 s in (EC − 0.38) eV to 1.24 × 10− 5 s in (EC − 0.83) eV and rises slowly as the interface state energy is changed from the bottom of the conduction band (EC) towards the mid-gap. Extracted value of electron capture cross-section, σn ranges from ~ 2 × 10− 12 to ∼ 9 × 10− 13 cm2 and doping concentration, Nd shows a value of ∼ 4.97 × 1016 cm− 3.