Dose Nitrogen Implantation Research Articles

Identification and Expression Profiling of WRKY Family Genes in Sugarcane in Response to Bacterial Pathogen Infection and Nitrogen Implantation Dosage.

WRKY transcription factors (TFs) are essential players in different signaling cascades and regulatory networks involved in defense responses to various stressors. This study systematically analyzed and characterized WRKY family genes in the Saccharum spp. hybrid R570 and their expression in two sugarcane cultivars LCP85-384 (resistant to leaf scald) and ROC20 (susceptible to leaf scald) in response to bacterial pathogen infection and nitrogen implantation dosage. A total of 53 ShWRKY genes with 66 alleles were systematically identified in R570 based on the query sequence SsWRKY in S. spontaneum AP85-441. All ShRWKY alleles were further classified into four groups with 11 (16.7%) genes in group I, 36 (54.5%) genes in group II, 18 (27.3%) genes in group III, and 1 (1.5%) gene in group IV. Among them, 4 and 11 ShWRKY gene pairs displayed tandem and segmental duplication events, respectively. The ShWRKY genes exhibited conserved DNA-binding domains, which were accompanied by variations in introns, exons, and motifs. RT-qPCR analysis of two sugarcane cultivars triggered by Xanthomonas albilineans (Xa) revealed that four genes, ShWRKY13-2/39-1/49-3/125-3, exhibited significant upregulation in leaf scald-resistant LCP85-384. These WRKY genes were downregulated or unchanged in ROC20 at 24–72 h post-inoculation, suggesting that they play an important role in defense responses to Xa infection. Most of the 12 tested ShWRKYs, ShWRKY22-1/49-3/52-1 in particular, functioned as negative regulators in the two cultivars in response to a range of nitrogen (N) implantation doses. A total of 11 ShWRKY proteins were predicted to interact with each other. ShWRKY43 and ShWRKY49-3 are predicted to play core roles in the interaction network, as indicated by their interaction with six other ShWRKY proteins. Our results provide important candidate gene resources for the genetic improvement of sugarcane and lay the foundation for further functional characterization of ShWRKY genes in response to coupling effects of Xa infection and different N levels.

Nitrogen implantation of zinc arsenic tellurite glasses

We have implanted xZnF2–(20-x)ZnO–40As2O3–40TeO2 (x = 4 and 20 mol%) glasses with nitrogen ions at different doses. The glass samples were characterized by Rutherford backscattering spectrometry for the concentration depth profiles of the implanted atoms, by SEM analysis for surface morphology, and also by UV–vis absorption spectroscopy. It was observed that in both the glass systems, there is an increase in the values of penetration depth R, projected range Rp, and straggle ΔRp as the N+ implantation dose grows from 5 × 1016 to 5 × 1017 ions/cm2. Scanning electron micrographs show a considerable change in the surface topography between the unimplanted and nitrogen-implanted regions. After nitrogen ion implantation, the transmittance was found to decrease while the absorption edge shifts towards higher wavelength with the increase in the nitrogen implantation doses in both the glass systems. The observed reduction in optical band gap in the both the glass systems can be attributed to the effect of band tailing due to the defects produced during nitrogen implantation.

Influences of pre-oxidation nitrogen implantation and post-oxidation annealing on channel mobility of 4H-SiC MOSFETs

Detailed investigations on the pre-oxidation nitrogen implantation and post-oxidation annealing processes for the improvement of channel mobility and specific on-resistance in 4H-SiC MOSFETs are reported. The results indicate that higher temperature and time for NO nitridation annealing process lead to higher field-effect channel mobility and lower specific on-resistance attributed to the good interface properties of SiC and SiO2 of MOSFETs. Furthermore, more nitrogen implantation energy and dose improved the channel mobility and specific on-resistance due to higher Id and less fixed charge, traps, and defects at the SiO2/SiC interface. The threshold voltages and blocking performance of MOSFETs are influenced by pre-oxidation nitrogen implantation conditions attributed to changing of counter doping mechanism in the DMOSFET p-well.

Structure evolution and mechanical properties of Ta–Nb–Ti–W–N multielement films

In this study, the multielement films (Ta50·5Nb16·7Ti8·8W24·0)N, (Ta25·4Nb13·4Ti20·9W40·3)N and (Ta9·3Nb4·7Ti22·6W63·4)N are prepared by combining magnetron sputtering deposition and nitrogen plasma based ion implantation (N-PBII). The composition, structure and mechanical properties of the films are investigated. X-ray diffraction patterns show that the alloy films Ta50·5Nb16·7Ti8·8W24·0, Ta25·4Nb13·4Ti20·9W40·3 and Ta9·3Nb4·7Ti22·6W63·4 are composed of hcp+bcc, two types of bcc and a single bcc solid solution respectively, whereas all the Ta–Nb–Ti–W films are composed of bcc and fcc structures after N-PBII treatment. The lattice constant increases for both the bcc and fcc phases, while it decreases for the Ta and Nb concentrations in the films. The hardness and modulus of the Ta–Nb–Ti–W–N films are improved with increasing nitrogen implantation dose. The wear rate of the Ta25·4Nb13·4Ti20·9W40·3 with nitrogen implantation for 1 h is decreased two times than the Ta25·4Nb13·4Ti20·9W40·3 alloy films.

Impact of Fabrication Process on Electrical Properties and on Interfacial Density of States in 4H-SiC n-MOSFETs Studied by Hall Effect

In this work, electrical properties of lateral n-channel MOSFETs implanted with differentnitrogen doses in the channel region were measured by Hall-effect technique at 300K. A mobility improvement with increasing nitrogen implantation doses is observed. Interface trap density (Dit) was determined from the experimentally measured Hall carrier density. Our results show a high Dit near and within the conduction band that does not change significantly when the nitrogen implantation dose is increased, despite observed mobility improvement.

Chemical state and phase structure of (TaNbTiW)N films prepared by combined magnetron sputtering and PBII

(TaNbTiW)N films with thickness of ∼1000nm are prepared on titanium alloy substrate by combined magnetron sputtering deposition and nitrogen plasma based ion implantation (N-PBII). Chemical state of the elements and phase structure of the films are investigated using X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD), respectively. The bonds of TaN, NbN, TiNO and TaO are detected in the (TaNbTiW)N films, however both WN and WO are not found. The initial alloy film has a BCC structure, while the films with N-PBII treatment are composed of BCC and FCC structures. The hardness and elastic modulus of the films can be improved by increasing nitrogen implantation dose and reach maximum values of 9.0GPa and 154.1GPa, respectively.

Hall Effect Characterization of 4H-SiC MOSFETs: Influence of Nitrogen Channel Implantation

Effect of a shallow nitrogen implantation in the channel region of n-channel 4H-SiC Hall bar MOSFETs on their electrical properties has been characterized by Hall effect. A significant improvement of Hall mobility in normally-off devices is observed with increasing nitrogen implantation dose up to 1013 cm-2 with a peak Hall mobility of 42.4 cm2.V-1.s-1. Coulomb scattering as dominant scattering mechanism up to room temperature is demonstrated using temperature dependent MOS-Hall effect characterization.

Influence of Nitrogen Implantation on Electrical Properties of Al/SiO<sub>2</sub>/4H-SiC MOS Structure

In this article, an influence of nitrogen implantation dosage on SiC MOS structure is analyzed using wide range of nitrogen implantation dose (between ~1013 – 1016). Authors analyzed electrical and material properties of investigated samples using C-V, I-V measurements, Raman spectroscopy, and XPS profiling. It has been shown that surface state trap density is directly connected to implantation damage and thus implantation conditions. Using research results a trap origin at given energy can be concluded.

Total dose radiation response of modified commercial silicon-on-insulator materials with nitrogen implanted buried oxide

Nitrogen ions of various doses are implanted into the buried oxide (BOX) of commercial silicon-on-insulator (SOI) materials, and subsequent annealings are carried out at various temperatures. The total dose radiation responses of the nitrogen-implanted SOI wafers are characterized by the high frequency capacitance-voltage (C—V) technique after irradiation using a Co-60 source. It is found that there exist relatively complex relationships between the radiation hardness of the nitrogen implanted BOX and the nitrogen implantation dose at different irradiation doses. The experimental results also suggest that a lower dose nitrogen implantation and a higher post-implantation annealing temperature are suitable for improving the radiation hardness of SOI wafer. Based on the measured C—V data, secondary ion mass spectrometry (SIMS), and Fourier transform infrared (FTIR) spectroscopy, the total dose responses of the nitrogen-implanted SOI wafers are discussed.

Dose Influence on Physical and Electrical Properties of Nitrogen Implantation in 3C-SiC on Si

In this paper, we studied the influence of nitrogen implantation dose on both physical and electrical properties in 3C-SiC grown on Si (100) substrate. Scanning Transmission Electron Microscopy characterizations prove that high dose is responsible for amorphization of the implanted layer and the high defect density after annealing. A high V-shape defect density is still found in the implanted layer after an annealing at 1350°C. By lowering the dose, the layer is less damaged and no amorphization is observed. For the different doses, low Specific Contact Resistances are measured using Ti/Ni contacts. The Specific Contact Resistance value decreases from 8x10-6 Ω.cm2 for the high dose to 3.2x10­6 Ω.cm2 with decreasing the dose. Furthermore, the dopant activation ratio, evaluated by quantitative SSRM measurements, is improved at the same time from 17% (for the high dose) to 60% (for the low dose). This work demonstrates that high activation ratio can be achieved consecutively to a nitrogen implantation at reasonable implantation fluence.

Magnetism of a Nitrogen-Implanted TiO2 Single Crystal

Single rutile crystal TiO2 was implanted using nitrogen ions with energy of 60 keV. The microstructure, ultraviolet-visible light absorption spectra, conductivity and magnetism are investigated. Except for the nitrogen dopant, no impurity can be detected by x-ray diffraction and x-ray photoelectron spectra. The absorption in the visible light region is enhanced with nitrogen implantation dose increasing. By measuring the temperature dependence of resistance, it is found that the sample implanted with 1 × 1018 ions/cm2 is changes from insulating to semiconducting, and the variable range hopping is the main conducting mechanism. Room-temperature ferromagnetism is also obtained in this sample. The magnetism as a function of temperature can be well fitted using the three-dimensional spin wave model plus the Curie-Weiss model, indicating that there is a mixed phase of ferromagnetism and paramagnetism.

Tuning Carbon-Based Fuel Cell Catalyst Support Structures via Nitrogen Functionalization. II. Investigation of Durability of Pt–Ru Nanoparticles Supported on Highly Oriented Pyrolytic Graphite Model Catalyst Supports As a Function of Nitrogen Implantation Dose

Nitrogen functionalization of carbon-based support materials for low-temperature fuel cell catalysts has been shown to improve catalyst–support interactions and therefore enhance both the performan...

Tuning Carbon-Based Fuel Cell Catalyst Support Structures via Nitrogen Functionalization. I. Investigation of Structural and Compositional Modification of Highly Oriented Pyrolytic Graphite Model Catalyst Supports as a Function of Nitrogen Implantation Dose

Surface modification and doping of graphitic-carbon catalyst support materials in fuel cell systems, particularly via nitrogen functionalization, has been shown to improve catalyst performance and durability through the optimization of catalyst–support interactions. To ascertain the nature of these interactions, Raman and X-ray photoelectron spectroscopy were used to study the structural and chemical modifications that nitrogen ion beam implantation caused to highly oriented pyrolitic graphite (HOPG) model catalyst support systems. Ion implantation doses explored in this work ranged over 2 orders of magnitude from 9.0 × 1014 to 9.6 × 1016 ions cm–2. Low doses of nitrogen result in a large amount of structural damage with little incorporation of nitrogen. However, it was found that with increasing dosage the incremental increase in structural damage was marginal, while the percentage of nitrogen on the HOPG surface continued to increase significantly until both the level of damage and amount of nitrogen in...

Influence of nitrogen implantation on the localized corrosion resistance of different tempers of AA7075 aluminium alloy

AbstractThis paper reports the study of the effect of nitrogen implantation on the localized corrosion resistance of the passive layers generated on different tempers of AA7075 aluminium alloy.Cyclic potentiodynamic polarization has been employed to analyze the resistance to localized corrosion of the alloys in a chloride medium, whereas exfoliation corrosion susceptibility test (EXCO‐Test) have been performed to evaluate the influence of nitrogen implantation on exfoliation resistance.Results show that nitrogen implantation (dose of 2 × 1017 N+ ions/cm2 and energy of 50 keV) does not have a clear positive effect on exfoliation resistance as it is evident on EXCO testing. However, electrochemical experiments performed in 1 mM NaCl solution reveal a light increase on localized corrosion resistance on implanted alloys. Moreover, the results demonstrate that the susceptibility of the 7075 aluminium alloy to different types to localized corrosion such as, pitting, intergranular and exfoliation greatly depends on the aging treatment, even under implantation conditions. Copyright © 2010 John Wiley & Sons, Ltd.

Influence of nitrogen dose on the charge density of nitrogen-implanted buried oxide in SOI wafers

To harden silicon-on-insulator (SOI) wafers fabricated using separation by implanted oxygen (SIMOX) to total-dose irradiation, the technique of nitrogen implantation into the buried oxide (BOX) layer of SIMOX wafers can be used. However, in this work, it has been found that all the nitrogen-implanted BOX layers reveal greater initial positive charge densities, which increased with increasing nitrogen implantation dose. Also, the results indicate that excessively large nitrogen implantation dose reduced the radiation tolerance of BOX for its high initial positive charge density. The bigger initial positive charge densities can be ascribed to the accumulation of implanted nitrogen near the Si-BOX interface after annealing. On the other hand, in our work, it has also been observed that, unlike nitrogen-implanted BOX, all the fluorine-implanted BOX layers show a negative charge density. To obtain the initial charge densities of the BOX layers, the tested samples were fabricated with a metal-BOX-silicon (MBS) structure based on SIMOX wafers for high-frequency capacitance–voltage (C–V) analysis.

Practical realization of dual-gate-oxide technology concept using ultra-shallow nitrogen r.f. plasma implantation with plasma and thermal oxidation

In mixed logic/memory circuits manufactured as a system on chip, two different thicknesses of dielectric layers are required. Simultaneous formation of both layers is possible if oxidation of a silicon layer is preceded by local nitrogen implantation, since the rate of oxidation depends on the nitrogen implantation dose and its profile. Experiments presented in this work show a possibility and an attempt of practical realization of controlling a very thin dielectric layer's thickness by preceding the oxidation with an ultra-shallow nitrogen implantation from r.f. plasma. As opposed to the methods presented in the literature so far, where classical implanters or the ion immersion implantation plasma (IIIP) technique were used for ultra-shallow implantation, our process is performed in a typical PECVD planar plasma reactor. The r.f. plasma nitrogen implantation has been carried out from NH 3 plasma and then immediately followed by the thermal- or plasma-oxidation process. The electrophysical properties of the obtained layers and systems (ultrathin dielectric layer, silicon) were characterized by electrical methods. Results of ellipsometric, XPS and ULE-SIMS measurements are also presented and discussed.

Effect of implantation of nitrogen into SIMOX buried oxide on its fixed positive charge density

In order to obtain greater radiation hardness for SIMOX (separation by implanted oxygen) materials, nitrogen was implanted into SIMOX BOX (buried oxide). However, it has been found by the C-V technique employed in this work that there is an obvious increase of the fixed positive charge density in the nitrogen-implanted BOX with a 150 nm thickness and 4×1015cm-2 nitrogen implantation dose, compared with that unimplanted with nitrogen. On the other hand, for the BOX layers with a 375 nm thickness and implanted with 2×1015 and 3×1015cm-2 nitrogen doses respectively, the increase of the fixed positive charge density induced by implanted nitrogen has not been observed. The post-implantation annealing conditions are identical for all the nitrogen-implanted samples. The increase in fixed positive charge density in the nitrogen-implanted 150 nm BOX is ascribed to the accumulation of implanted nitrogen near the BOX/Si interface due to the post-implantation annealing process according to SIMS results. In addition, it has also been found that the fixed positive charge density in initial BOX is very small. This means SIMOX BOX has a much lower oxide charge density than thermal SiO2 which contains a lot of oxide charges in most cases.

Research on the effect of nitrogen implantation doses on the structure of separation byimplantation of oxygen and nitrogen

In our work, separation by implantation of oxygen and nitrogen (SIMON) wafers werefabricated with different nitrogen implantation doses and post-annealing. Secondary ion massspectrometer (SIMS) analysis showed that for the samples with low nitrogen dose somenitrogen ions were distributed in the buried oxide layers and some others were collected at theSi/SiO2 interface after annealing, and for the samples with large nitrogen dose distinct delaminationappeared between the layer containing the nitrogen element and that containing the oxygenelement. The results of the spreading resistance probe (SRP) suggested that a buriedinsulator was formed for wafers with large nitrogen implantation dose. The results of crosssection transmission electron microscopy (XTEM) confirmed the analysis above. Theresults show that the quality of SIMON materials is closely related to nitrogenimplantation parameters.

Effect of the technology of implanting nitrogen into buried oxide on the radiation hardness of the top gate oxide for partially depleted SOI PMOSFET

The effect of implanting nitrogen into buried oxide on the top gate oxide hardness against total irradiation does has been investigated with three nitrogen implantation doses (8 x 10(15), 2 x 10(16) and 1 x 10(17) cm(-2)) for partially depleted SOI PMOSFET. The experimental results reveal the trend of negative shift of the threshold voltages of the studied transistors with the increase of nitrogen implantation dose before irradiation. After the irradiation with a total dose of 5 x 10(5) rad(Si) under a positive gate voltage of 2V, the threshold voltage shift of the transistors corresponding to the nitrogen implantation dose 8 x 10(15) cm(-2) is smaller than that of the transistors without implantation. However, when the implantation dose reaches 2 x 10(16) and 1 x 10(17) cm(-2), for the majority of the tested transistors, their top gate oxide was badly damaged due to irradiation. In addition, the radiation also causes damage to the body-drain junctions of the transistors with the gate oxide damaged. All the results can be interpreted by tracing back to the nitrogen implantation damage to the crystal lattices in the top silicon.

Effects of Techniques of Implanting Nitrogen into Buried Oxideon the Characteristics of Partially Depleted SOI PMOSFET

Effects of techniques of implanting nitrogen into buried oxide on thecharacteristics of the partially depleted silicon-on-insulator (SOI)p-channel metal-oxide-semiconductor field-effect transistors (PMOSFETs)have been studied with three different nitrogen implantation doses,8×1015, 2×1016, and 1×1017 cm−2. Theexperimental results show that this technology can affect the thresholdvoltage, channel hole mobility and output characteristics of thepartially depleted SOI PMOSFETs fabricated with the given material andprocess. For each type of the partially depleted SOI PMOSFET withnitrided buried oxide, the absolute value of the average thresholdvoltage increases due to the nitrogen implantation. At the same time,the average channel hole mobility decreases because of the nitrogenimplantation. In particular, with the high nitrogen implantation doses,the output characteristic curves of the tested transistors present adistinct kink effect, which normally exists in the characteristic output curves of only partially depleted SOI NMOSFETs.