| 1. |
- Carlberg, Patrick, et al.
(författare)
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Lift-off process for nanoimprint lithography
- 2003
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Ingår i: Microelectronic Engineering. - 0167-9317 .- 1873-5568. ; 67-8, s. 203-207
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Konferensbidrag (refereegranskat)abstract
- We report a novel a lift-off method for nanoimprint lithography. This is a bi-layer method, using a polymethyl methacrylate (PMMA) on lift-off layer (LOL) resist scheme. For the imprint step, direct evidence for good pattern transfer down to 20 nm is shown. Oxygen plasma ashing is required to remove residual PMMA. A liquid solvent, MF 319, is used to transfer the pattern down to the silicon. The LOL is dissolved isotropically while the PMMA is unaffected. Ashing time can kept to a minimum through the wet etch method. This reduces the line widening effect. After metal evaporation a two-step lift-off process prevents metal flakes from adhering to the surface electrostatically. At first warm acetone breakes apart the metal layer and dissolves the PMMA, then warm Remover S-1165 removes the LOL and remaining metal. Structures of lines down to 50 nm and dots with a diameter of sub 20 nm are presented.
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| 2. |
- Finder, C, et al.
(författare)
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Fluorescence microscopy for quality control in nanoimprint lithography
- 2003
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Ingår i: Microelectronic Engineering (Proceedings of the 28th International Conference on Micro- and Nano-Engineering). - 0167-9317 .- 1873-5568. ; 67-8, s. 623-628
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Konferensbidrag (refereegranskat)abstract
- Fluorescence microscopy is introduced as a low cost quality control process for nanoimprint lithography. To depict imprinted structures down to 1 mum lateral size and to detect residues down to 100 nm lateral size, the standard printable polymer mr-18000 is labelled with less than 0.1 wt.% fluorescent dye. Three different types of stamps are used to determine the dependence of the shape and size of stamp features in a series of imprints. The quality of a stamp is given by the sticking polymer residues per unit area. Fluorescence light images as well as visible light images are analysed. Changes in the area of the stamp covered with polymer as a function of the number of imprints is summarised in a statistical process chart. Adhesion was artificially induced in order to observe self cleaning of virgin stamps. They were detected and monitored, suggesting that this method is a suitable technique for quality control and that it could be easily adapted to the nanoimprint process. (C) 2003 Elsevier Science B.V. All rights reserved.
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| 3. |
- Maximov, Ivan, et al.
(författare)
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Fabrication of Si-based nanoimprint stamps with sub-20 nm features
- 2002
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Ingår i: MICROELECTRONIC ENGINEERING. - 1873-5568 .- 0167-9317. ; 61-2, s. 449-454
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Konferensbidrag (refereegranskat)abstract
- We present two alternative methods for fabrication of nanoimprint lithography stamps in SiO2 with sub-20 nm features: (a) optimized electron beam lithography (EBL) and lift-off patterning of a 15-nm thick Cr mask, and (b) aerosol deposition of W particles in the 20-nm size range. In both cases, the pattern transfer into SiO2 was performed using reactive ion etching (RIE) with CHF3 as etch gas. In the first approach, we used a double layer resist system (PMMA/ZEP 520A7 positive resists) for the EBL exposure. Resist thickness, exposure dose and development time were optimized to obtain 15-20 nm features after Cr lift-off. In the second approach, we used size selected W aerosol particles as etch masks during etching of SiO2. Both methods of stamp fabrication are compared and discussed. (C) 2002 Published by Elsevier Science B.V.
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| 4. |
- Zankovych, S, et al.
(författare)
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Nanoimprint-induced effects on electrical and optical properties of quantum well structures
- 2003
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Ingår i: Microelectronic Engineering (Proceedings of the 28th International Conference on Micro- and Nano-Engineering). - 0167-9317 .- 1873-5568. ; 67-8, s. 214-220
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Konferensbidrag (refereegranskat)abstract
- A study of optical and transport properties of semiconductor quantum well structures subjected to nanoimprint lithography (NIL), with its pressure and temperature cycles, has been undertaken to ascertain if this lithography technique induces detrimental changes in these properties of the active layers over a range of pressures and temperatures, typically used in this printing process. Ga0.47In0.53As-InP and GaAs-Al0.3Ga0.7As multiple quantum well samples were investigated. Luminescence and the photoluminescence excitation were recorded before and after printing. No impact upon the luminescence energy and intensity were detected. From the photoluminescence spectrum no evidence of induced strain was found. The magneto transport experiments yielded no evidence of deterioration of neither the mobility nor carrier concentration of a two-dimensional electron gas in a modulation-doped Ga0.25In0.75As/InP heterostructure. Results on samples subjected to the NIL process over a wide range of applied pressure and temperature are presented and discussed. (C) 2003 Elsevier Science B.V. All rights reserved.
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| 5. |
- Boström, Mathias, et al.
(författare)
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Temperature effects on the Casimir attraction between a pair of quantum wells
- 2000
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Ingår i: Microelectronic Engineering. - 0167-9317 .- 1873-5568. ; 51, s. 287-297
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Tidskriftsartikel (refereegranskat)abstract
- We present calculations of the free energy of attraction between two quantum wells in which the wells are treated as strictly two-dimensional metallic sheets. The van der Waals force exhibits fractional separation dependence in this system. This is in contrast to the usual integer separation dependence. We have performed numerical calculations at different temperatures and with different carrier densities. Except at very low temperatures thermal effects will be a dominating source of attraction. We have determined temperature criteria that must be fulfilled for the fractional separation dependence to be observable. Thermal corrections will be important already at temperatures less than 1 K. We further make some comments on a recent measurement of the Casimir force.
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| 6. |
- Edholm, Bengt, et al.
(författare)
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Electrical investigation of the silicon/diamond interface
- 1997
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Ingår i: Microelectronic Engineering. - 0167-9317 .- 1873-5568. ; 36:1-4, s. 245-248
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Tidskriftsartikel (refereegranskat)abstract
- A new method for measuring the interface properties, using diamond terminated silicon p-n diodes, is used to quantify the electrical quality and to determine the conduction mechanism of the silicon/diamond interface for two types of diamond. It was found
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| 7. |
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| 8. |
- Ewert, Tony, et al.
(författare)
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Investigation of the electrical behavior of an asymmetric MOSFET
- 2003
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Ingår i: Microelectronic Engineering. - 0167-9317 .- 1873-5568. ; 65:4, s. 428-438
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Tidskriftsartikel (refereegranskat)abstract
- In this study a possible approach for improving breakdown voltage while maintaining fT for a MOSFET, is presented. In a conventional MOSFET process with LDD the S/D is implanted with a large tilt angle, which gives an asymmetry due to the shadowing effect by the gate. This asymmetry results in a longer drain-LDD region, which in combination with a lower LDD dose, could reduce the electrical field near the drain pinch-off region. A simulation study for different LDD doses and angles has been performed. It is shown that there exist an optimum range of LDD doses where the asymmetric device has higher figure-of-merit, concerning breakdown voltage and cut-off frequency, than the symmetric MOSFET structure.
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| 9. |
- Gudmundson, Peter, et al.
(författare)
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Stresses in thin films and interconnect lines
- 2002
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Ingår i: Microelectronic Engineering. - 0167-9317 .- 1873-5568. ; 60:1-2, s. 17-29
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Tidskriftsartikel (refereegranskat)abstract
- The mechanical behavior of thin films and interconnect lines is investigated. Firstly, theoretical models of thermal stress evolution in thin films and passivated or unpassivated lines are considered. Secondly, the effect of texture in a copper thin film with a columnar grain structure is studied from a theoretical point of view. The film consists of three different constituents with (111), (100) and randomly oriented texture. Global properties as well as local stress distributions are considered in detail within a thermoelastic framework. The results are in qualitative agreement with available experimental results. Implications with regards to plastic behavior are briefly discussed. Finally, the potential of the curvature measurement technique for experimental stress evaluation in thin films is considered for initially flat and curved substrate/film systems.
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| 10. |
- Hansson, B. A. M., et al.
(författare)
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A liquid-xenon-jet laser-plasma X-ray and EUV source
- 2000
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Ingår i: Microelectronic Engineering. - 0167-9317 .- 1873-5568. ; 53:04-jan, s. 667-670
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Tidskriftsartikel (refereegranskat)abstract
- We describe a laser-plasma soft-x-ray source based on a cryogenic-xenon liquid-jet target. The source is suitable for extreme ultraviolet (EUV) projection lithography and proximity x-ray lithography (PXL). Absolute calibrated spectra in the 1-2 nm range and uncalibrated spectra in the 9-15 nm range are obtained using a free-standing transmission grating and a CCD-detector.
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