High dielectric constant nickel-doped titanium oxide films prepared by liquid-phase deposition

The electrical characteristics of nickel-doped titanium oxide films prepared by liquid-phase deposition on p-type (100) silicon substrate were investigated. The aqueous solutions of ammonium hexafluorotitanate and boric acid were used as precursors for the growth of titanium oxide films and the dielectric constant is 29. The dielectric constant can be improved to 94 by nickel doping at the thermal annealing at 700 °C in nitrous oxide.     

Thin TiO2 grown by metal–organic chemical vapor deposition on (NH4)2S x -treated InP

The electrical characteristics of thin TiO₂ films prepared by metal–organic chemical vapor deposition grown on a p-type InP substrate were studied. For a TiO₂ film of 4.7 nm on InP without and with ammonium sulfide treatment, the leakage currents are 8.8×10⁻² and 1.1×10⁻⁴ A/cm² at +2 V bias and 1.6×10⁻¹ and 8.3×10⁻⁴ A/cm² at −2 V bias. The lower leakage currents of TiO₂ with ammonium sulfide treatment arise from the improvement of interface quality. The dielectric constant and effective oxide charge number density are 33 and 2.5×10¹³ cm², respectively. The lowest mid-gap interface state density is around 7.6×10¹¹ cm⁻² eV⁻¹. The equivalent oxide thickness is 0.52 nm. The breakdown electric field increases with decreasing thickness in the range of 2.5 to 7.6 nm and reaches 9.3 MV/cm at 2.5 nm.     

Electrical characteristics of GaAs MOS capacitor and field effect transistor with atomic layer-deposited TiO2/Al2O3 dielectrics

The (NH₄)₂S treatment can reduce native oxides and passivate GaAs. Atomic layer-deposited Al₂O₃ can further remove the residue native oxides by self-cleaning. Stacked with high dielectric constant TiO₂ prepared by atomic layer deposition on Al₂O₃/(NH₄)₂S-treated GaAs MOS capacitor, the leakage current densities can reach 4.5 × 10^?8 and 3.4 × 10^?6 A/cm² at ±2 MV/cm. The net effective dielectric constant of the entire stack is 18 and the interface state density is about 4.2 × 10¹¹/cm²/eV. The fabricated enhancement-mode n-channel GaAs MOSFET exhibited good electrical characteristics with a maximum g _m of 122 mS/mm and electron mobility of 226 cm²/V s.     

Characterization of SiON/InP MOS structure with sulfidation, fluorination, and hydrogenation

Liquid phase deposited SiON film on InP with (NH₄)₂S treatment shows superior electrical characteristics due to the reduction of native oxides and sulfur passivation. Simultaneously, HF in SiON liquid phase deposition solution can effectively reduce residual native oxides on InP and provide fluorine passivation in SiON/InP film and interface. With post-metallization annealing (PMA), hydrogen ions can further passivate defects in SiON/InP film and interface. With these treatments, the PMA-LPD-SiON/(NH₄)₂S-treated InP MOS structure shows excellent electrical characteristics. With the physical thickness of 5.4 nm, the leakage current densities can be as low as 1.25×10^?7 and 6.24×10^?7 A/cm² at ±2 V, and the interface state density is 3.25×10¹¹ cm^?2?eV^?1.