| 1. |
- Astromskas, Gvidas, et al.
(författare)
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Temperature and frequency characterization of InAs nanowire and HfO2 interface using capacitance-voltage method
- 2011
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Ingår i: Microelectronic Engineering. - : Elsevier BV. - 1873-5568 .- 0167-9317. ; 88:4, s. 444-447
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Konferensbidrag (refereegranskat)abstract
- InAs/HfO2 nanowire capacitors using capacitance-voltage (CV) measurements are investigated in the range of 10 kHz to 10 MHz. The capacitors are based on vertical nanowire arrays that are coated with an 8 nm-thick HfO2 layer by atomic layer deposition. CV characteristics are measured at temperatures in the range between -140 and 40 degrees C and the CV characteristics for nanowires with different Sn and Se n-type doping levels are compared. The comparison of the data at various doping levels points towards large number of traps for highly doped samples, caused by the preferential dopant precursor incorporation at the nanowire surface. We also evaluate the frequency dispersion of the accumulation capacitance and determine values below 2% with weak temperature dependence, indicating the existence of border traps in these nanowire capacitors. (C) 2010 Elsevier B.V. All rights reserved.
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| 2. |
- Chubarova, Elena, et al.
(författare)
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Platinum zone plates for hard X-ray applications
- 2011
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Ingår i: Microelectronic Engineering. - : Elsevier BV. - 0167-9317 .- 1873-5568. ; 88:10, s. 3123-3126
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Tidskriftsartikel (refereegranskat)abstract
- We describe the fabrication and evaluation of platinum zone plates for 5–12 kV X-ray imaging and focusing. These nano-scale circular periodic structures are fabricated by filling an e-beam generated mold with Pt in an electroplating process. The plating recipe is described. The resulting zone plates, having outer zone widths of 100 and 50 nm, show good uniformity and high aspect ratio. Their diffraction efficiencies are 50–70% of the theoretical, as measured at the European Synchrotron Radiation Facility. Platinum shows promise to become an attractive alternative to present hard X-ray zone plate materials due to its nano-structuring properties and the potential for zone-plate operation at higher temperatures.
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| 3. |
- Garidis, Konstantinos, et al.
(författare)
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Mask roughness impact on extreme UV and 193 nm immersion lithography
- 2012
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Ingår i: Microelectronic Engineering. - : Elsevier BV. - 0167-9317 .- 1873-5568. ; 98, s. 138-141
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Tidskriftsartikel (refereegranskat)abstract
- The contribution of mask absorber line edge roughness on printed resist lines is studied for extreme UV and 193 nm immersion lithography. Programmed roughness modules were designed for roughness transfer function evaluation on 88 nm pitch line space patterns. The tested modules were designed applying variations of roughness amplitude and spatial frequency. Power spectral density analysis was performed on top-down SEM images. The effect of frequency roughness filtering by the lithographic optical system was studied with different illumination settings. It was found that, except for the degradation of the aerial image due to the filtering effect, less performing illuminations show an increased deterioration of the aerial image quality and thus contribute further to line edge roughness. A comparison with previous work was completed on different mask architectures and photoresist platforms. Resist performance can attenuate the roughness transfer from mask but at the cost of worse chemical gradient at the edges of the exposed regions.
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| 4. |
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| 5. |
- Graczyk, Mariusz, et al.
(författare)
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Fabrication of bottle-shaped nanochannels in fused silica using a self-closing effect
- 2012
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Ingår i: Microelectronic Engineering. - : Elsevier BV. - 1873-5568 .- 0167-9317. ; 97, s. 173-176
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Tidskriftsartikel (refereegranskat)abstract
- The spatial control of molecular motor function, using nanostructured surfaces, is of great interest for the development of commercial devices for diagnostics and high-throughput drug screening with molecular motors as targets. In the present study we have fabricated 100-300 nm wide nanochannels, completely subsurfaced on fused silica chips, with the aim to interface them with a microfluidic system. Such a system will allow for changes in the chemical environment surrounding molecular motors, with minimal influence on their directional motion. This will be achieved by changing the chemical environment in a perpendicular direction to the motor motion and allowing the chemical substances to diffuse in and out of the nanochannels via a small slit (5-10 nm) on the top of the nanochannels. To create this slit, and to control its width, we here demonstrate the use of a self-closing effect based on the volume increase (2.27 times) during oxidation of silicon. The details of the fabrication steps (EBL, RIE and oxidation) are discussed. (C) 2012 Elsevier B.V. All rights reserved.
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| 6. |
- Jafri, S Hassan M, et al.
(författare)
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Control of junction resistances in molecular electronic devices fabricated by FIB
- 2011
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Ingår i: Microelectronic Engineering. - : Elsevier BV. - 0167-9317 .- 1873-5568. ; 88:8, s. 2629-2631
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Tidskriftsartikel (refereegranskat)abstract
- A major hurdle to realize molecular electronic devices (MEDs) is to make reliable electrical contacts to a single or a few molecules. Our nano-contact platform with a gap size of less than 25 nm with resistances above 1000 TΩ was built using combined techniques of photolithography, electron beam lithography and focused ion beam milling. In this study, we have used gold nanoparticles (AuNPs) to bridge the nanoelectrode gaps by dielectrophoretic trapping and thus obtain electrical contacts. The electrodes and/or the nanoparticles were functionalised with 1–2 nm long alkane-thiol molecules so that the electronic structure of these molecules determines the properties of the electrical junction. Molecules were introduced both by functionalising the nanogap and the nanoparticles and the results of both functionalisation protocols are compared. Here, we show the nanogap–nanoparticle bridge set-up containing metal–molecule junctions that can be used as a base for the development of molecular electronics containing only a few molecules under ambient conditions. Current–voltage (I–V) characterization of alkanethiol/gold junction showed non-linear response where mean geometric resistance of four different junctions could be tuned from 20 GΩ to 20 TΩ. The results from the measurements on 1-alkanethiol in such devices is a first step to demonstrate that this platform has the potential to obtain stable electronic devices having relatively small numbers of molecules with reliable metal molecule junction by combing top-down and bottom-up approaches.
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| 7. |
- Jogi, Indrek, et al.
(författare)
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Atomic layer deposition of high capacitance density Ta2O5-ZrO2 based dielectrics for metal-insulator-metal structures
- 2010
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Ingår i: Microelectronic Engineering. - : Elsevier BV. - 0167-9317 .- 1873-5568. ; 87:2, s. 144-149
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Tidskriftsartikel (refereegranskat)abstract
- We have investigated electrical properties of laminated atomic layer deposited films: ZrO2-Ta2O5, ZrO2-Nb2O5-Ta2O5, ZrO2-TaxNb1-xO5 and Ta2O5-ZrxNbyOz. Even though the capacitances of laminates were often higher compared to films of constituent materials with similar thickness, considerably higher charge storage factors, Q were achieved only when tetragonal ZrO2 was stabilized in ZrO2-Ta2O5 laminate and when the laminate thickness exceeded 50 rim. The decreased Q values in the case of most laminates were the result of increased leakage currents. In the case of thinner films only Ta2O5-ZrxNbyOz, stack possessed capacitance density and Q value higher than reference HfO2. Concerning the conduction mechanisms, in the case of thinner films, the Ta2O5 or TaxNb1-xO5 apparently controlled the leakage either by Richardson-Schottky emission or Poole-Frenkel effect. (C) 2009 Elsevier B.V. All rights reserved
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| 8. |
- Johansson, Sofia, et al.
(författare)
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Temperature and annealing effects on InAs nanowire MOSFETs
- 2011
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Ingår i: Microelectronic Engineering. - : Elsevier BV. - 0167-9317 .- 1873-5568. ; 88:7, s. 1105-1108
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Konferensbidrag (refereegranskat)abstract
- We report on temperature dependence on the drive current as well as long-term effects of annealing in vertical InAs nanowire Field-Effect Transistors. Negatively charged traps in the HfO2 gate dielectric are suggested as one major factor in explaining the effects observed in the transistor characteristics. An energy barrier may be correlated with an un-gated InAs nanowire region covered with HfO2 and the effects of annealing may be explained by changed charging on defects in the oxide. Initial simulations confirm the general effects on the I-V characteristics by including fixed charge. (c) 2011 Elsevier B.V. All rights reserved.
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| 9. |
- Karlsson, Mikael, et al.
(författare)
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Fabrication of sub-micron high aspect ratio diamond structures with nanoimprint lithography
- 2010
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Ingår i: Microelectronic Engineering. - : Elsevier BV. - 0167-9317 .- 1873-5568. ; 87:11, s. 2077-2080
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Tidskriftsartikel (refereegranskat)abstract
- Polycrystalline diamond with optical quality has been patterned using nanoimprint lithography. Nanoimprint lithography is a rather new method for fabrication of resist structures with features sizes down to at least 20 nm. The pattern used in this article is a grating with a period of 600 nm and a fill factor of 0.5. Using plasma etching the nanoimprinted grating is etched into a freestanding diamond substrate. We have accomplished the fabrication of 300 nm diamond features with a depth of about 2 mu m, which corresponds to an aspect ratio of 7.
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| 10. |
- Luo, Jun, et al.
(författare)
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Effects of carbon pre-silicidation implant into Si substrate on NiSi
- 2014
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Ingår i: Microelectronic Engineering. - : Elsevier BV. - 0167-9317 .- 1873-5568. ; 120, s. 178-181
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Tidskriftsartikel (refereegranskat)abstract
- In this work, the effects of carbon pre-silicidation implant into Si(1 0 0) substrate on NiSi were investigated. NiSi films with carbon pre-silicidation implant to different doses were characterized by means of sheet resistance measurements, X-ray diffraction, scanning electron microscopy (SEM), planar view transmission electron microscopy (TEM) and second ion mass spectroscopy (SIMS). The presence of C is found to indeed significantly improve the thermal stability of NiSi as well as tends to change the preferred orientations of polycrystalline NiSi. The homogeneously distributed C at NiSi grain boundaries and C peak at NiSi/Si interface is ascribed to the improved thermal stability of NiSi. More importantly, the dose of carbon pre-silicidation implant also plays a key role in the formation of NiSi, which is suggested not to exceed a critical value about 5 x 10(15) cm(-2) in practical application in accordance with the results achieved in this work. (C) 2013 Elsevier B.V. All rights reserved.
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