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In current work, effects of rapid thermal annealing on the interface chemical bonding states, band alignment, and electrical properties of atomic-layer-deposition-derived HfAlO/Al 2 O 3 gate stack on Si substrates have been studied by X-ray photoemission spectroscopy (XPS), UV–Vis transmission spectroscopy, and electrical measurements. XPS analyses have shown that HfAlO alloy and mixed silicate (Hf-Al-O-Si) increase after post-deposition annealing process. By means of UV–Vis transmission spectroscopy measurements, reduction in band gap for 400 o C-annealed sample has been observed. Accordingly, reduction in the valence band offset and increase in the conduction band offset have been detected for HfAlO/Al 2 O 3 /Si gate stack annealed at 400 °C. Various current conduction mechanisms, such as Poole-Frenkel emission, Fowler-Nordheim (FN) tunneling, and space-charge-limited (SCL) conduction, have been analyzed. Detailed electrical measurements reveal that current conduct mechanisms is SCL conduction at lower field region and FN tunneling and SCL conduction are dominant conduction mechanism at higher field region. [ABSTRACT FROM AUTHOR]

Deposition of HfTiO x gate dielectric films on n-type Si and quartz substrates by sol–gel technique has been performed and the optical, electrical characteristics of the as-deposited HfTiO x thin films as a function of baking temperature have been investigated. The components and optical properties of HfTiO x thin films related to baking temperature are investigated by energy dispersive spectrometer (EDS), ultraviolet–visible spectroscopy (UV–Vis), and spectroscopy ellipsometry (SE). By measurement of EDS, the Hf/Ti molar ratio of HfTiO x thin films is calculated to be about 1:1.20 at all baking temperature. The increase in band gap is observed with the increase of baking temperature. Additionally, the electrical properties based on Al/Si/HfTiO x /Al capacitor are analyzed by means of the high frequency capacitance-voltage ( C-V ) and the leakage current density-voltage ( J-V ) characteristics. Results have shown that 200 °C-baked sample demonstrates good electrical performance, including larger dielectric constant of 23.31 and lower leakage current density of 5.12 × 10 −5 A/cm 2 at the gate voltage of 1 V. Additionally, the leakage current conduction mechanisms as functions of baking temperatures are also discussed systematically. [ABSTRACT FROM AUTHOR]

High-k gate dielectric HfTiO x thin films have been deposited on Si and quartz substrate by radio frequency (RF) magnetron sputtering. The structural and optical properties of HfTiO x thin films related to deposition power are investigated by X-ray diffraction (XRD), ultraviolet–visible spectroscopy (UV–Vis), and spectroscopic ellipsometry (SE). Results indicate that the as-deposited HfTiO x thin films are amorphous state regardless of the deposition power. The increase of band gap of the samples is observed with the increase of deposition power. Moreover, the increase of the thickness, deposition rate, refractive index (n) and the decrease of the extinction coefficient with the increase of deposition power are also confirmed. Additionally, the electrical properties of films are analyzed by measurement of high frequency capacitance–voltage ( C–V ) and leakage current density-voltage ( J-V ) characteristics. And the leakage current conduction mechanisms are also discussed. [ABSTRACT FROM AUTHOR]

The effect of boron (B) doping on the microstructure, band gap energy and electrical properties of ZrO 2 gate dielectrics deposited by sol–gel method at low temperature were systemically investigated. By means of characterization of spectroscopy ellipsometry and ultraviolet–visible spectroscopy, the thicknesses and optical constants of ZrO 2 gate dielectrics have been determined precisely. The B incorporation dependent electrical properties of ZrO 2 films were determined by capacitance–voltage ( C–V ) and leakage current density–voltage ( J–V ) measurements. The dominant conduction mechanisms of Al/B:ZrO 2 / n -Si MOS structures have been discussed systematically in detail. As a result, the optimized B incorporation content has been obtained to achieve ZrO 2 gate dielectrics with high quality. [ABSTRACT FROM AUTHOR]

The effects of substrate temperature ( T s ) on the electrical and optical properties of amorphous InGaZnO thin films deposited by sputtering have been investigated. As T s increased from RT to 400 °C, all the films remained amorphous, the transmission in the visible region increased from 92.8% to 93.54%, and the band gap decreased from 3.42 eV to 3.31 eV. Based on Cauchy–Urbach model, the optical properties of all samples were analyzed by spectroscope ellipsometry (SE) and increase in refractive index has been detected with the increase in T s . Results of Hall measurement showed that substrate temperature have remarkable influence on the resistivity ( ρ ), carrier concentration ( n ), and carrier mobility ( μ ) of IGZO films. As T s increased from RT to 400 °C, ρ decreased from 46.6 to 0.24 Ω cm, and then increased to 1.11 Ω cm at T s of 400 °C, and n increase from 5.67 × 10 15 to 7.33 × 10 18 cm −3 . Investigation of X-ray photoelectron spectroscopy (XPS) indicated that as T s increased, an O 1 s component representing the oxygen vacancies increased in amount and that the intensity ratio of In/Ga increased but that of Zn/Ga decreased. The analysis suggests that the increase of oxygen vacancies could explain the increase in n and reduction in ρ and that the compositional change could explain the change of E g . [ABSTRACT FROM AUTHOR]