Structural, optical and electrical properties of high-k ZrO_2 dielectrics on Si prepared by plasma assisted pulsed laser deposition

摘要

ZrO_2 films were grown on p-type Si(100) using plasma assisted pulsed laser deposition and the electrical characteristics of the ZrO_2 dielectrics incorporated in metal oxide silicon (MOS) capacitors were studied in combination with their structural and optical properties. The ZrO_2 dielectric layers are of polycrystalline structure with a monoclinic phase and show good interfacial properties without obvious SiO_x interface. The electrical performance of the capacitors exhibits typical MOS-type capacitance-voltage (C-V) and leakage current density-voltage (J-V) characteristics. Thermal annealing of the ZrO_2 dielectrics results in an improvement in C-V and J-V characteristics and a reduction in C-V hysteresis without obvious introduction of leakage paths for the fabricated MOS capacitors. The dielectric constant was calculated to be 15.4 and the leakage current density was measured to be 6.7 × 10~(-6) A/cm~2 at a gate voltage of +1.0 V for 900 ℃ annealed ZrO_2 dielectric layers with an equivalent oxide thickness of 5.2 nm.