Nitrided SrTiO 3 as charge-trapping layer for nonvolatile memory applications

Charge-trapping characteristics of SrTiO 3 with and without nitrogen incorporation were investigated based on Al/ Al 2 O 3/SrTiO 3/SiO 2 /Si (MONOS) capacitors. A Ti-silicate interlayer at the SrTiO 3/SiO 2 interface was confirmed by x-ray photoelectron spectroscopy and transmission electron microscopy. Compared with the MONOS capacitor with SrTiO 3 as charge-trapping layer (CTL), the one with nitrided SrTiO 3 showed a larger memory window (8.4 V at ±10 V sweeping voltage), higher P/E speeds (1.8 V at 1 ms +8 V) and better retention properties (charge loss of 38% after 10 4s), due to the nitrided SrTiO 3 film exhibiting higher dielectric constant, higher deep-level traps induced by nitrogen incorporation, and suppressed formation of Ti silicate between the CTL and SiO 2 by nitrogen passivation. © 2011 American Institute of Physics.published_or_final_versio

Improved performance by using TaON/SiO2 as dual tunnel layer in Charge-Trapping nonvolatile memory

postprin

A novel MONOS memory with high-κ HfLaON as charge-storage layer

MIS capacitors with a high-κ HfLaON or HfLaO gate dielectric are fabricated by using a reactive sputtering method to investigate the applicability of the films as a novel charge-storage layer in a metaloxidenitrideoxidesilicon nonvolatile memory device. Experimental results indicate that the MIS capacitor with a HfLaON gate dielectric exhibits a large memory window, high program/erase speed, excellent endurance property, and reasonable retention. The involved mechanisms for these promising characteristics with HfLaON are thought to be in part from nitrogen incorporation leading to higher density of traps with deeper levels and, thus, higher trapping efficiency, stronger HfN and LaN bonds, and more stable atomic structure and HfLaONSiO 2 interface, as compared to the HfLaO dielectric. © 2011 IEEE.published_or_final_versio

Improved charge-trapping properties of HfYON film for nonvolatile memory applications in comparison with HfON and Y 2O 3 films

The charge-trapping properties of HfYON film are investigated by using the Al/HfYON/SiO 2/Si structure. The physical features of this film were explored by transmission electron microscopy and x-ray photoelectron spectroscopy. The proposed device shows better charge-trapping characteristics than samples with HfON or Y 2O 3 as the charge-trapping layer due to its higher trapping efficiency, as confirmed by extracting their charge-trap centroid and charge-trap density. Moreover, the Al/Al 2O 3/HfYON/SiO 2/Si structure shows high program speed (4.5 V at 14 V, 1 ms), large memory window (6.0 V at 14 V, 1 s), and good retention property, further demonstrating that HfYON is a promising candidate as the charge-trapping layer for nonvolatile memory applications. © 2011 American Institute of Physics.published_or_final_versio

Improved performance of yttrium-doped Al 2O 3 as inter-poly dielectric for flash-memory applications

Yttrium-doped Al 2O 3Y xAl yO) with different yttrium contents prepared by co-sputtering method is investigated as the inter-poly dielectric (IPD) for flash memory applications. A poor SiO 2-like interlayer formed at the IPD/Si interface is confirmed by X-ray photoelectron spectroscopy, and can be suppressed by Y doping through the transformation of silica into silicate. Compared with Al 2O 3 and Y 2O 3 films, the optimized Y xAl yO film shows lower interface-state density, lower bulk charge-trapping density, higher dielectric constant, and smaller gate leakage, due to the suppressed interlayer and good thermal property ascribed to appropriate Y and Al contents in the film. Therefore, the optimized Y xAl yO film is a promising candidate as the IPD for flash memory. © 2010 IEEE.published_or_final_versio

Compressibility effects on the scalar mixing in reacting homogeneous turbulence

The compressibility and heat of reaction influence on the scalar mixing in decaying isotropic turbulence and homogeneous shear flow are examined via data generated by direct numerical simulations (DNS). The reaction is modeled as one-step, exothermic, irreversible and Arrhenius type. For the shear flow simulations, the scalar dissipation rate, as well as the time scale ratio of mechanical to scalar dissipation, are affected by compressibility and reaction. This effect is explained by considering the transport equation for the normalized mixture fraction gradient variance and the relative orientation between the mixture fraction gradient and the eigenvectors of the solenoidal strain rate tensor.Comment: In Turbulent Mixing and Combustion, eds. A. Pollard and S. Candel, Kluwer, 200

Electrical and FT-IR measurements of undoped N-type INP materials grown from various stoichiometric melts

P-rich, In-rich and Stoichiometric undoped InP melts have been synthesed by phosphorus in-situ injection method. InP crystal ingots have been grown from these melts by Liquid Encapsulated Czochralski (LEC). Samples from these ingots grown from various Stoichiometric melts have been characterized by Hall Effect and Fourier Transform Infrared (FT-IR) spectroscopy measurements respectively. The Hall Effect measurement results indicate that the net carrier concentration of P-inch undoped InP is higher than that of In-rich and Stoichiometric undoped InP materials. FT-IR spectroscopy measurements reveal that there are intensive absorption peaks which have been proved to be hydrogen related indium vacancy complex V InH 4. By comparing FT-IR spectra, it is found that P-rich InP material has the most intensive absorption peak of V InH 4, while In-rich InP material has the weakest absorption peak.published_or_final_versio

Thermally induced conduction type conversion in n-type InP

n-type semiconducting InP is changed into p-type semiconducting by short time annealing at 700 °C. Further annealing for a longer time leads to a second conduction-type conversion changing the material back to n type again but with a much higher resistivity. These conduction conversions indicate the formation of both acceptor and donor defects and the progressive variation of their relative concentrations during annealing. © 1999 American Institute of Physics.published_or_final_versio

The depth-profiled carrier concentration and scattering mechanism in undoped GaN film grown on sapphire

The carrier concentration and scattering mechanism in undoped GaN film grown on sapphire were investigated. The film was grown on sapphire using metal organic chemical vapor deposition (MOCVD). Confocal micro-Raman spectroscopic measurements and temperature-dependant Hall (TDH) measurements were performed for the study of the depth distribution of the carrier density across the GaN film. The existence of a nonuniform spatial distribution of free carriers in the film with a highly conductive layer of ∼1 μm thickness near the GaN sapphire boundary was confirmed from the study. The electron mobility limiting effect of nitrogen vacancies on GaN bulk film was also discussed.published_or_final_versio

Effects of a type-II RNA-binding protein on fatty acid composition in Synechocystis sp. PCC 6803

In the cyanobacterium Synechocystis 6803, rbp3, a type-II RNA-binding protein gene, is slightly induced by temperature downshift. An rbp3 mutant shows significant reduction in total polyunsaturated fatty acids (PUFA) in membrane lipids. However, the reduction in PUFA has not attained the extent that would significantly affect the growth of the mutant at low temperature. Transcripts of fatty acid desaturase genes desA, desB and desD, and ccr-1, a gene required for growth at 15°C, are significantly reduced in the mutant relative to the wild type, while transcripts of rbp1 (RNA-binding protein 1) and crhR (RNA helicase Light) are not affected. Rbp3 may directly or indirectly affect mRNA levels of certain genes