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Metal-oxide-semiconductor capacitors with Pr2O3/oxynitride laminated gate dielectrics were fabricated. The current transportation of Al/Pr2O3/SiON/n-Si devices was studied at temperatures ranging from 300 to 400 K. The dominant conduction mechanism at low electric field (<0.6 MV/cm) is the hopping conduction in the laminated gate dielectrics. The determined hopping distance and activation energy is about 1.5 nm and 50±1 meV, respectively. However, the dominant conduction mechanism at high electric field (>2 MV/cm) is the Poole–Frenkel emission in which the trap energy level determined from Arrhenius plot is about 0.56±0.01 eV. [ABSTRACT FROM AUTHOR]

This paper describes the structure and electrical properties of thin NdOxNy gate dielectrics deposited on Si(100) substrates through reactive rf sputtering. Atomic force microscopy and x-ray photoelectron spectroscopy were used to study the morphological and chemical features of these films as functions of the growth conditions (argon-to-nitrogen flow ratios of 20/5, 15/10, 10/15, and 5/20; temperatures ranging from 600 to 800 °C). The NdOxNy gate dielectric prepared under an Ar/N2 flow ratio of 10/15 with subsequent annealing at 700 °C exhibited the smallest capacitance equivalent thickness and the best electrical characteristics (gate leakage current, interface-trapped charge, and hysteresis voltage in the capacitance-voltage curves). We attribute this behavior to the optimal nitrogen content in this metal oxide film suppressing the amorphous silica and silicate at the NdOxNy/Si interface and forming a smooth surface. [ABSTRACT FROM AUTHOR]

The structural properties and electrical characteristics of metal-oxide-nitride-oxide-silicon memory structure by using praseodymium oxide (Pr2O3) or praseodymium titanium oxide (PrTixOy) to replace silicon nitride as the charge storage layer [resulting structure is termed metal–oxide–high-k material–oxide–silicon (MOHOS) devices] were investigated. The structural and morphological features of these high-k films were analyzed using x-ray diffraction, scanning electron microscopy, atomic force microscopy, and x-ray photoelectron spectroscopy. It was found that MOHOS memory prepared under the PrTixOy film and annealed at 800 °C exhibited a large flatband voltage shift of 5.6 V and low charge loss of ∼6% at room temperature. We attribute this behavior to the titanium content in the Pr2O3 film, suppressing interfacial SiO2 and silicate from forming at the PrTixOy/oxide interface and enhancing nanocrystal formation. [ABSTRACT FROM AUTHOR]

The structural properties and electrical characteristics of thin Nd2O3 gate oxides were deposited on silicon substrates by reactive rf sputtering. The structural and morphological features of these films were studied, as a function of the growth conditions (three various argon-to-oxygen flow ratios: 20/5, 15/10, and 12.5/12.5 and temperature from 600 to 800 °C), by x-ray diffraction, atomic force microscopy, and x-ray photoelectron spectroscopy. It is found that Nd2O3 dielectrics with a 12.5/12.5 ratio condition annealed at 700 °C exhibit a thinner capacitance equivalent thickness and excellent electrical properties, including the electric breakdown field, the interface trap density, the hysteresis, and frequency dispersion in the capacitance-voltage curves. This condition is suggested to the reduction of the interfacial SiO2 and silicate formation, and the small of surface roughness due to the optimization of oxygen in the metal oxide film. [ABSTRACT FROM AUTHOR]

High-k cobalt-titanium oxide (CoTiO[sub 3]) and nickel-titanium oxide (NiTiO[sub 3]) were formed by directly oxidizing sputtered Co/Ti and Ni/Ti film. Al/CoTiO[sub 3]/Si[sub 3]N[sub 4]/Si and Al/NiTiO[sub 3]/Si[sub 3]N[sub 4]/Si capacitor structures were fabricated and measured. The effective dielectric constant (k value≅45) with buffer layer for CoTiO[sub 3] is larger than that of NiTiO[sub 3]. In addition, CoTiO[sub 3] depicts excellent electrical properties at the same time. This metal oxide thus appears to be a very promising high-k gate dielectric for future ultralarge scale integrated devices. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

We investigated the impact of Ti doping in the Sm2O3 dielectric on the electrical stress-induced instability in amorphous indium-gallium-zinc oxide (a-IGZO) thin-film transistors (TFTs). With increasing stress time in a-IGZO TFT devices, a small initial positive shift followed by a negative shift of threshold voltage is characterized in the Sm2O3 dielectric, whereas only positive shift of threshold voltage is observed for Ti-doped Sm2O3 dielectric. The positive shift of the threshold voltage can be explained by charge trapping in the Sm2O3 film and/or the Sm2O3/IGZO interfaces, while the negative shift of threshold voltage is probably due to the extra charges from the IGZO channel by self-heating effect. [ABSTRACT FROM AUTHOR]

We investigate the resistive memory switching behaviors of Yb2O3 thin films for different Ti-dopant concentrations. A higher doping concentration of 9.4% of Ti atom into Yb2O3 thin film causes the switching mechanism to change from bipolar to unipolar behavior. This is ascribed to different chemical compositions of the filament through the oxide film. The reset mechanism is associated with the annihilation of oxygen vacancies and other ionic and electronic defects within or near the interface area of oxide film for bipolar switching, while it is believed to be due to rupture of the conducting filament by local Joule heating effect for unipolar resistive switching. Furthermore, the incorporation of Ti atom into the Yb2O3 memory device exhibits improved electrical performances including low set/reset voltages and good endurance and retention characteristics. [ABSTRACT FROM AUTHOR]

Solid-state sensors are stable and inexpensive electric transducers for biomedical measurement. This study proposes a microfluidic chip incorporated with a solid-state sensor for measuring glucose and creatinine in blood serum. Magnetic beads are employed to immobilize enzymes and deliver them in a micro-channel. Glucose and creatinine can be measured at 2-8 mM and 10-2 to 10 mM, respectively, which is a meaningful range in human blood. The immobilization approach also addresses the issue of the long-term preservation of enzymes in microfluidic devices. The proposed device is suitable for multi-target measurement in a point-of-care system. [ABSTRACT FROM AUTHOR]

In this study, we reported the forming-free resistive switching behavior in the Ru/RE2O3/TaN (RE = Nd, Dy, and Er) memory devices using thin Nd2O3, Dy2O3, and Er2O3 films fabricated with full room temperature process. The dominant conduction mechanisms of the Ru/RE2O3/TaN devices in the low-resistance state and high-resistance state are Ohmic behavior. The Ru/Dy2O3/TaN memory device exhibited high resistance ratio, nondestructive readout, reliable data retention, and good endurance. Ru/Dy2O3/TaN memory device has a great potential for the application in nonvolatile resistive switching memory. [ABSTRACT FROM AUTHOR]

In this letter, we proposed a metal-oxide-high-k-oxide-silicon (MOHOS)-type memory structure using a high-k Yb2O3 charge trapping layer for flash memory applications. When using Fowler-Nordheim for charging and discharging, the high-k Yb2O3 MOHOS-type memories that had been annealed at 800 °C exhibited large threshold voltage shifting (memory window of ∼2.2 V) and excellent data retention (charge loss of ∼6% measured time up to 104 s and at room temperature) because of the higher probability for trapping the charge carrier due to the formation of the Yb-silicate layer and the smooth surface roughness. [ABSTRACT FROM AUTHOR]

In this letter, we study the structural and electrical properties of high-k neodymium titanium oxide (NdTiO3) gate dielectrics deposited on Si (100) substrates by reactive rf sputtering. We find that the capacitance value of NdTiO3 gate dielectric prepared at a 6 nm Ti metal film is higher than other thicknesses and exhibits a lower hysteresis voltage and interface trap density in capacitance-voltage curves. This result is attributed to an amorphous NdTiO3 structure and the suppression of the interfacial layer observed from x-ray diffraction and x-ray photoelectron spectroscopy, respectively. [ABSTRACT FROM AUTHOR]

In this letter, the authors propose the formation of stacked oxide/Y2TiO5/oxide layers for flash memory application. The quality of a high-k Y2TiO5 memory was examined by x-ray diffraction, x-ray photoelectron spectroscopic, atomic force microscopy, capacitance-voltage curves, and data retention. When using Fowler-Nordheim for charging and discharging, the Y2TiO5 memory annealed at 900 °C for 30 s exhibited large flatband-voltage shifting (memory window of 4.2 V) and superior data retention (charge loss of 6% at room temperature) because of the higher probability for trapping the charge carriers and they trapped in the deep trap level of Y2TiO5 due to the formation of a well-crystallized Y2TiO5 structure and the reduction of Y-silicate layer. [ABSTRACT FROM AUTHOR]

In this letter, the authors reported a high-k neodymium oxide gate dielectric grown by reactive rf sputtering. It is found that the Nd2O3 gate dielectric after annealing at 700 °C exhibits excellent electrical properties such as low equivalent oxide thickness, high electric breakdown field, and almost no hysteresis and frequency dispersion in C-V curves. This indicates that annealing at 700 °C treatment can prevent the interfacial layer and silicate formation, reduce a large amount of interface trap, and passivate a large amount of trapped charge at defect sites. [ABSTRACT FROM AUTHOR]

High-k cobalt-titanium oxide (CoTiO[sub 3]) film was formed by directly oxidizing sputtered Co/Ti or Ti/Co films. Al/CoTiO[sub 3]/Si[sub 3]N[sub 4]/Si capacitor structures were fabricated and measured. Excellent electrical properties with an effective dielectric constant (i.e., k value) as high as 40 have been achieved for a CoTiO[sub 3] gate dielectric with a buffer layer. The metal-oxide thus appears to be a very promising high-k gate dielectric for future ultralarge scale integrated devices. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

We investigate the electrical stress-induced instability in amorphous indium-gallium-zinc oxide (a-IGZO) thin-film transistors (TFTs) with Sm2O3 gate dielectrics. Tow-step electrical degradation behavior in Sm2O3 a-IGZO TFT devices was found under high gate and drain voltage stress during 1000 s. A typical small positive shift followed by an unusual negative shift of threshold voltage is characterized in our TFT devices. We believe that the positive shift of the threshold voltage is due to charge trapping in the gate dielectric and/or at the channel/dielectric interfaces, while the negative shift of threshold voltage can be attributed to the generation of extra electrons from oxygen vacancies in the a-IGZO channel. We suggested that the amount of oxygen vacancies and the quality of the high-κ gate dielectric probably affect the degradation behavior of a-IGZO TFT devices. [ABSTRACT FROM AUTHOR]

In this study, we developed a high-performance low-temperature polycrystalline silicon thin-film transistor (LTPS-TFT) incorporating an ultra thin Eu2O3 gate dielectric. High-κ Eu2O3 LTPS-TFT annealed at 500 °C exhibits a low threshold voltage of 0.16 V, a high effective carrier mobility of 44 cm2/V-s, a small subthreshold swing of 142 mV/decade, and a high Ion/Ioff current ratio of 1.34 × 107. These significant improvements are attributed to the high gate-capacitance density due to the adequate quality of Eu2O3 gate dielectric with small interfacial layer of effective oxide thickness of 2.5 nm. Furthermore, the degradation mechanism of positive bias temperature instability was studied for a high-k Eu2O3 LTPS-TFT device. [ABSTRACT FROM AUTHOR]

A response by Tung-Ming Pan and Chih-Hung Lu to a letter to the editor on their article regarding the analysis of the composition and chemical bonding in RE2O3 films in the February 13, 2012 issue is presented.