Irradiation effects and hydrogen behavior in H2+ and He+ implanted γ-LiAlO2 single crystals
Not Available
Jiang, Weilin↗
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Improved ion implant fluence uniformity in hydrogen enhanced glow discharge plasma immersion ion implantation into silicon
Enhanced glow discharge plasma immersion ion implantation does not require an external plasma source but ion focusing affects the lateral ion fluence uniformity, thereby hampering its use in high-fluence hydrogen ion implantation for thin film transfer and fabrication of silicon-on-insulator. Insertion of a metal ring between the sample stage and glass chamber improves the ion uniformity and reduces the ion fluence non-uniformity as the cathode voltage is raised. Two-dimensional multiple-grid particle-in-cell simulation confirms that the variation of electric field inside the chamber leads to mitigation of the ion focusing phenomenon and the results are corroborated experimentally by hydrogen forward scattering.
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
Molecular ion sources for low energy semiconductor ion implantation (invited)
Smaller semiconductors require shallow, low energy ion implantation, resulting space charge effects, which reduced beam currents and production rates. To increase production rates, molecular ions are used. Boron and phosphorous (or arsenic) implantation is needed for P-type and N-type semiconductors, respectively. Carborane, which is the most stable molecular boron ion leaves unacceptable carbon residue on extraction grids. A self-cleaning carborane acid compound (C{sub 4}H{sub 12}B{sub 10}O{sub 4}) was synthesized and utilized in the ITEP Bernas ion source resulting in large carborane ion output, without carbon residue. Pure gaseous processes are desired to enable rapid switch among ion species. Molecular phosphorous was generated by introducing phosphine in dissociators via 4PH{sub 3} = P{sub 4} + 6H{sub 2}; generated molecular phosphorous in a pure gaseous process was then injected into the HCEI Calutron-Bernas ion source, from which P{sub 4}{sup +} ion beams were extracted. Results from devices and some additional concepts are described.
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
Effects of Channel Implant Variation on Radiation-Induced Edge Leakage Currents in n-Channel MOSFETs
The effects of radiation-induced defects and statistical variation in the dose and energy of MOSFET channel implants in a modern bulk CMOS technology are modeled using a process simulator in combination with analytical computations. The model integrates doping profiles obtained from process simulations and experimentally determined defect potentials into implicit surface potential equations. Solutions to these equations are then used to model radiation-induced edge leakage currents in 90-nm bulk CMOS n-channel MOSFETs. The results indicate that slight variations in the channel implant parameters can have a significant impact on the doping profile along the shallow trench isolation sidewall and thus the radiation-induced edge leakage currents.
42 ENGINEERING↗
Structural and electrical properties of In-implanted Ge
We report on the effects of dopant concentration on the structural and electrical properties of In-implanted Ge. For In concentrations of ≤ 0.2 at. %, extended x-ray absorption fine structure and x-ray absorption near-edge structure measurements demonstrate that all In atoms occupy a substitutional lattice site while metallic In precipitates are apparent in transmission electron micrographs for In concentrations ≥0.6 at. %. Evidence of the formation of In-vacancy complexes deduced from extended x-ray absorption fine structure measurements is complimented by density functional theory simulations. Hall effect measurements of the conductivity, carrier density, and carrier mobility are then correlated with the substitutional In fraction.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Atomistic simulations of tungsten surface evolution under low-energy neon implantation
Tungsten is a candidate material for the divertor of fusion reactors, where it will be subject to a high flux of particles coming from the fusion plasma as well as a significant heat load. Under helium plasma exposure in fusion-reactor-like conditions, a nanostructured morphology is known to form on the tungsten surface in certain temperature and incident energy ranges, although the formation mechanism is not fully established. A recent experimental study (Yajima et al 2013 Plasma Sci. Technol. 15 282-6) using neon or argon exposure did not produce similar nanostructure. Here, this article presents molecular dynamics simulations of neon implantation in tungsten aimed at investigating the surface evolution and elucidating the role of noble gas mass in fuzz formation. Finally, in contrast to helium, neon impacts can sputter both tungsten and previously implanted neon atoms. The shorter range of neon ions, along with sputtering, limit the formation of large bubbles and likely prevents nanostructure formation.
70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
Implantation of nitrogen: Effects of hydrogen and implantation energy
To solve the question on solar nitrogen in lunar soils, i.e. variation in isotopic composition and apparently high retentivity compared with rare gases, nitrogen implantation experiments were conducted. At the Meteoritical Society Meeting in Copenhagen, the results of stepped combustion of implanted nitrogen in ilmenite and olivine were presented. The degassing behavior of nitrogen (and also Ar) was quite different from that observed in the case of lunar soils. Extraction temperatures are higher (greater than 1100 C for ilmenite and 1500 C for olivine) than that for lunar soils. Both nitrogen and Ar seem to be retained at the same efficiency. Therefore, additional experiments were conducted to make degassing behavior of nitrogen more close to that observed in the case of lunar soils.
Sugiura, Naoji↗
Magnesium behavior and structural defects in Mg+ ion implanted silicon carbide
Not Available
Jiang, Weilin↗
From Metal-Organic Frameworks to Single-Atom Fe Implanted N-doped Porous Carbons: Efficient Oxygen Reduction in Both Alkaline and Acidic Media [From MOFs to Single Fe Atoms Implanted N-doped Porous Carbons: Efficient Oxygen Reduction in Both Alkaline and Acidic Media]
Here, it remains highly desired but a great challenge to achieve atomically dispersed metals in high loadings for efficient catalysis. Now porphyrinic metal–organic frameworks (MOFs) have been synthesized based on a novel mixed–ligand strategy to afford high–content (1.76 wt %) single–atom (SA) iron–implanted N–doped porous carbon (Fe SA –N–C) via pyrolysis. Thanks to the single–atom Fe sites, hierarchical pores, oriented mesochannels and high conductivity, the optimized Fe SA –N–C exhibits excellent oxygen reduction activity and stability, surpassing almost all non–noble–metal catalysts and state–of–the–art Pt/C, in both alkaline and more challenging acidic media. More far–reaching, this MOF–based mixed–ligand strategy opens a novel avenue to the precise fabrication of efficient single–atom catalysts.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Fabrication and characterization of a co-planar detector in diamond for low energy single ion implantation
We demonstrate low energy single ion detection using a co-planar detector fabricated on a diamond substrate and characterized by ion beam induced charge collection. Histograms are taken with low fluence ion pulses illustrating quantized ion detection down to a single ion with a signal-to-noise ratio of approximately 10. We anticipate that this detection technique can serve as a basis to optimize the yield of single color centers in diamond. In conclusion, the ability to count ions into a diamond substrate is expected to reduce the uncertainty in the yield of color center formation by removing Poisson statistics from the implantation process.
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
Effect of C-He simultaneous implantation on deuterium retention in damaged W by Fe implantation
Not Available
Azuma, Keisuke↗