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The microstructure, optical and electrical properties of sputtering-derived HfGdO high-k gate dielectric thin films as a function of the Gd doping content have been systematically investigated. X-ray diffraction (XRD) measurements have indicated that Gd doping can form a new stable cubic phase. The optical band gap of the HfGdO gate dielectrics increases gradually from 5.82 to 6.14 eV as the Gd doping concentration increases. The electrical properties, such as permittivity, oxide trapped charge density, border trap charge density and leakage current density of samples, are determined using a semiconductor device analyzer. The formation mechanism of leakage current is also discussed in detail. In addition, the interfacial properties of HfGdO/Si gate satcks were tested to establish the electrical properties. The excellent optoelectronic properties, such as the optical band gap of 5.95 eV, leakage current density of 8.33 × 10 −8 A/cm 2 at a bias voltage of 2 V, oxide trapped charge density of −1.06 × 10 12  cm −2 and a border trap charge density of zero and optimized interfacial properties were observed in the HfGdO thin films with sputtering power of 30 W, indicating that it may become a potential high-k gate dielectric in future complementary metal oxide semiconductor (CMOS) devices. [ABSTRACT FROM AUTHOR]

In this work, the interface chemistry and the reduction of GaAs surface species by using (NH 4 ) 2 S solution prior to Gd-doped HfO 2 (HGO) thin film deposition and the removal of Ga Oxides and elemental As by rapid thermal annealing (RTA) have been investigated by X-ray photoelectron spectroscopy (XPS). Additionally, the effect of the surface passivation and rapid thermal annealing on the electrical properties of MOS capacitors based on sputtering-derived HGO as gate dielectric on GaAs substrate has been detected by means of capacitance-voltage ( C-V ) and leakage current density-voltage ( J-V ) measurements. Based on electrical analysis, it can be noted that the constantly improvement of electrical properties, such as the decreases of flat band voltage (V fb ), hysteresis (ΔV fb ), oxide charge density (O ox ), border trapped oxide charge density (N bt ) and leakage current density, have been observed. Especially, the dielectric constant of 16.72, flat band voltage V fb of 1.19 V, hysteresis ΔV fb of 0.04 V, leakage current density of 1.54 × 10 −5 A/cm 2 at bias voltage of 1 V, total positive charge density and border trap charge density of 6.09 × 10 12 cm −2 and 2.54 × 10 11 cm −2 , respectively render 600 °C-annealed HGO thin films, potential high-k gate dielectrics in future CMOS devices. [ABSTRACT FROM AUTHOR]

Effects of nitrogen incorporation on the interface chemical bonding states, band alignment and electrical properties of sputtering-derived HfTiO high-k gate stacks on Ge substrates pretreated by trimethylaluminum (TMA) precursor have been investigated by X-ray photoemission spectroscopy (XPS), UV–vis transmission spectroscopy, and electrical measurements. XPS results indicate that incorporation of a moderate amount of nitrogen (3 sccm) incorporation can effectively suppress the formation of unstable GeO 2 and low-k germinate at the interfacial region. Meanwhile, reduction in band gap and valence band offset and increase in conduction band offset have been observed after nitrogen incorporation. Electrical properties were evaluated by capacitance-voltage ( C–V ) and leakage current density-voltage ( J–V ) measurements based on MOS capacitors. Small gate leakage current (4.13 × 10 −7 A/cm 2 at V g = 1 V), almost disappeared hysteresis, and large dielectric constant (19.6) that have been observed for MOS capacitor with HfTiON/Ge stacked gate dielectric with N 2 flow of 3 sccm. [ABSTRACT FROM AUTHOR]

In this work, the band gap, interfacial properties and electrical properties of Gd doped ZrO 2 high-k gate dielectric films deposited by solution method have been systematically investigated. Results have shown that Gd doping can increase band gap energy from 5.65 to 5.92 eV and effectively restrain the formation of low-k SiO x interfacial layer between dielectric and Si substrate. Moreover, the conduction band offset is increased from 2.57 to 3.06 eV by Gd doping, which effectively reduces the leakage current density to 1.8 × 10 −6 A/cm 2 . [ABSTRACT FROM AUTHOR]

HfAlO/Ge gate stack with Al 2 O 3 passivation layer and different Al 2 O 3 concentration in HfAlO layer has been deposited on Ge substrate by atomic layer deposition. Based on measurements from capacitance-voltage and current density-voltage curves, the evolution of the electrical properties of Ge-based MOS capacitors based on HfAlO/Al 2 O 3 /Ge gate stack has been determined as functions of precursor ratio and annealing temperature. It has been found that high annealing temperature and high Al 2 O 3 incorporation in HfAlO films can obtain improved electrical properties such as low hysteresis, low flat-band, low flat-band shift and low interface-state density. However, the oxide-charge density obviously increases with rising the annealing temperature and decreasing Al 2 O 3 incorporation in HfAlO film. By analysis and calculation, it can be noted that the samples annealed at 500 °C holds the lowest leakage current density and the change of the precursor ratio has no apparent effect in 500 °C-annealed Ge MOS capacitor. To investigate current conduction mechanism of Ge MOS capacitors employing HfAlO/Al 2 O 3 gate stacks, current density-voltage measurements have been carried out as functions of annealing temperature and precursor ratio. The involved leakage current conduction mechanisms of the as-deposited and 500 °C-annealed HfAlO/Al 2 O 3 /Ge MOS capacitors for substrate injection also have been discussed in detail. [ABSTRACT FROM AUTHOR]

Deposition of HfAlO 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 HfAlO x thin films as a function of annealing temperature have been investigated. The optical properties of HfAlO x thin films related to annealing temperature are investigated by ultraviolet-visible spectroscopy (UV–vis) and spectroscopy ellipsometry (SE). By measurement of UV–vis, average transmission of all the HfAlO x samples are about 85% owing to their uniform composition. And the increase in band gap has been observed with the increase of annealing temperature. Moreover, the increase of refractive index (n) and density with the increase of annealing temperature are obtained by SE measurements. Additionally, the electrical properties based on Al/Si/HfAlO 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 400 °C-annealed sample demonstrates good electrical performance, including larger dielectric constant of 12.93 and lower leakage current density of 3.75×10 −7 A/cm 2 at the gate voltage of 1 V. Additionally, the leakage current conduction mechanisms as functions of annealing temperatures are also discussed systematically. [ABSTRACT FROM AUTHOR]

In this letter, annealing temperature dependence on the structure, band gap energy and electrical properties of TiO 2 doped ZrO 2 gate dielectrics deposited by sol-gel method at low temperature were systemically investigated. The crystalline temperature of TiO 2 doped ZrO 2 is up to 600 °C. The transmittance and band gap value of the ZrTiO x film were about 75% and 4.0 eV, respectively. 300 °C-annealed ZrTiO x MOS capacitor with high dielectric constant of 34.9, a small hysteresis value of 0.004 and low leakage current density of 2.7 × 10 −4 A/cm 2 were obtained. The dominant conduction mechanisms of Al/ZrTiO 4 / n -Si MOS structures were schottky emission and ohmic conduction in the low electric field and direct tunneling in the high electric field. As a result, it can be concluded that sol-gel derived ZrTiO x gate dielectric displays potential application as is a promising candidate in future MOS electronic devices. [ABSTRACT FROM AUTHOR]

High- k HfO x N y and HfO 2 have been applied to amorphous InGaZnO ( a -IGZO) metal–oxide–semiconductor (MOS) capacitors as high-k gate dielectrics by using radio-frequency sputtering at room temperature. Effects of nitrogen incorporation on the optical band gap, band alignment and electrical properties of HfO x N y /IGZO/Si gate stacks have been systematically investigated by spectroscopic ellipsometry (SE), UV–vis spectroscopy, x-ray photoemission spectroscopy (XPS) and electrical measurements. Experimental results have confirmed the successful incorporation of nitrogen into HfO 2 films and reduction in band gap with the incorporation of nitrogen for HfO x N y thin films. Reduction in valence band offset and increase in conduction band offset have been observed for HfO x N y /IGZO gate stack. Electrical properties measurements for a -IGZO MOS capacitors based on HfO x N y gate dielectrics have indicated that nitrogen incorporation leads to the improved interface quality, increased dielectric constant, reduced hysteresis voltage, and decreased leakage current density. Meanwhile, the leakage current mechanism under gate injection for MOS capacitors based on HfO 2 and HfO x N y high-k gate dielectrics has been investigated systematically. [ABSTRACT FROM AUTHOR]