philip D prewett - Academia.edu (original) (raw)

Papers by philip D prewett

Research paper thumbnail of Simulation studies of Plasmon enchanced evanescent near-field optical lithography

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Research paper thumbnail of FIB direct write of ALD A1203 mask for silicon DRIE

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Research paper thumbnail of A quantitative comparison between helium ion and electron beam lithography on PMMA resist

Helium ion beam lithography (HIBL), an emerging technique that uses a sub-nanometre focused beam ... more Helium ion beam lithography (HIBL), an emerging technique that uses a sub-nanometre focused beam of helium ions to expose resist, has introduced an alternative to electron beam lithography (EBL) to extend beyond existing minimum feature sizes. HIBL has several advantages over EBL, including a higher patterning resolution due to a smaller spot size [1] and a reduced proximity effect due to low ion backscattering and deflection [2, 3]. However, there is yet to be a direct comparison of these two techniques on thin layer resists. Here, we present a quantitative and direct comparison study on EBL and HIBL with respect to sensitivity and proximity effects using poly(methyl methacrylate) (PMMA), an established benchmark EBL resist, leading to a demonstration of high resolution HIBL patterning of line arrays.

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Research paper thumbnail of Effects of focused ion beam dwell time on Nano fabrication

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Research paper thumbnail of Special issue on Nano Lithography 2013

Microelectronic Engineering, 2014

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Research paper thumbnail of Liquid-like behaviour of gold nanowire bridges

Applied Physics Letters, 2017

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Research paper thumbnail of Helium Ion Beam Lithography on Fullerene Molecular Resists for Sub-10 nm Patterning

Microelectronic Engineering, 2016

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Research paper thumbnail of Angular effects in focused ion beam milling of silicon

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Research paper thumbnail of Finite Element Study of a Micro-Opto-XRay Imaging Lens for Biomedical Applications

Micro-Electro-Opto-Mechanical-Systems or MOEMS have potential applications inter alia in biomedic... more Micro-Electro-Opto-Mechanical-Systems or MOEMS have potential applications inter alia in biomedical research. For instance, studies of the Bystander Effect require controlled irradiation of biological cells with focused X-rays to reveal the mechanisms occurring. X-ray focusing may be achieved using an adaptive optic micro-lens in which focusing is entirely reflective and therefore compatible with broad band illumination, an improvement over diffractive systems such as zone plates. Such a micro-lens can be microfabricated in the form of a bent-cantilever beam made from two dissimilar materials (polyimide and gold) in a thermal bimorph configuration, actuated with a micro heater. The parallel horizontal slots on the beam provide the transmission and focusing functions, while the heater provides control of the focal length through variation of the beam’s curvature. This novel system has been named 1D-MOXI (Micro-Opto-X-ray Imaging) and a basic system has already been made and tested thermo-mechanically. The present paper focuses on details of the geometry of the deformed slotted micro-beam lens element under thermally derived strain, using finite element analysis, and suggests an optimized MOEMS design, giving prescribed curvature of the lens through changing the number and the dimensions of the slots. The study reveals the localized stress and the small deviations of the micro-lens behavior from that of perfect spherical geometry. The focal length variation with temperature is compared with the experimental values and those predicted by an analytical model.

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Research paper thumbnail of Optimization of a novel micro-opto-X-ray imaging lens

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Research paper thumbnail of Micro/Nano X-Ray Tomography Reconstruction Tuning Using SEM Images for PEMFC Gas Diffusion Layers

X-ray micro/nano tomography is a powerful tool to reveal inside structures of a sample, either an... more X-ray micro/nano tomography is a powerful tool to reveal inside structures of a sample, either an IC chip or a porous material. A challenge in X-ray tomography is to select a correct threshold to ensure the reconstructed models as close to the reality as possible. This paper presents a study to use scanning electron microscope (SEM) images as references for

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Research paper thumbnail of 3D reconstruction of a micro pipette tip

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Research paper thumbnail of Characterisation of nanoporous materials using Focused Ion Beam milling method

ABSTRACT Focused Ion Beam (FIB) is generally used for machining of solid and bulk materials. Howe... more ABSTRACT Focused Ion Beam (FIB) is generally used for machining of solid and bulk materials. However, new applications such as FIB nanotomography of nanoporous surfaces require sputtering yield characterisation. This paper presents the study of the FIB sputtering yield of Ga+ on nanoporous catalyst layers (CL) of a polymer electrolyte fuel cell (PEFC) based on analytical calculations and SEM stereo imaging experiments. It is shown that a porosity of around 50% has a significant effect (approximately 400%) on the sputtering yield of materials.

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Research paper thumbnail of Micro/nano X-ray tomography reconstruction fine-tuning using scanning electron microscope images

The use of scanning electron microscope (SEM) images as references for threshold tuning of X-ray ... more The use of scanning electron microscope (SEM) images as references for threshold tuning of X-ray micro/nano computed tomography reconstruction is proposed. In this research, high-resolution SEM images were used to provide a good estimation of the fibre diameter in the surface of gas diffusion layers (GDL) (5-10 mum). The X-ray tomography reconstructed binary images containing 3D information, including both the surface and the inside volume. Using the SEM images of a particular feature in carbon fibres, GDL layers were compared with the reconstructed surface of that feature from X-ray tomography data and provided the threshold estimation for reconstruction of the whole structure. Fibre diameter and continuity of the material from both the CT reconstruction and SEM images were analysed to obtain the optimum reconstruction. A linear relationship between fibre diameter and threshold variation has been found for micro/nano tomography of GDL layers.

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Research paper thumbnail of Embossing of 3D ceramic microstructures

Microsystem …, 2002

... Piezoceramics such as lead zirconate titanate (PZT) have been widely used in MEMS applica-tio... more ... Piezoceramics such as lead zirconate titanate (PZT) have been widely used in MEMS applica-tions. ... 2. The PMMA micro-moulds can be made by various existing methods such as LIGA (German acronym for X-ray lithography, electrodeposition Fig. ...

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Research paper thumbnail of Design and fabrication of a micro Wankel engine using MEMS technology

Microelectronic engineering, 2004

... Research Centre for Micro Engineering and Nano Technology, School of Engineering, The Univers... more ... Research Centre for Micro Engineering and Nano Technology, School of Engineering, The University of Birmingham, Edgbaston, Birmingham B15 2TT, UK. ... Conventional SU-8 processes often create a trench with wide top and narrow bottom, known as the T-shape, which is ...

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Research paper thumbnail of The focusing performance of an aperiodic double layer metallic grating

Microelectronic Engineering, 2014

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Research paper thumbnail of Enhanced field emission from polysilicon emitters using porous silicon

… , 1996. IVMC'96., …, 1996

... Sci. Technol. B 14, (1996), in press 6. SE Huq, M. Huang, PRWilshaw and P. D. Prewett, submit... more ... Sci. Technol. B 14, (1996), in press 6. SE Huq, M. Huang, PRWilshaw and P. D. Prewett, submitted to IVMC'96 7. EC Boswell, M. Huang, GDW Smith and PR Wilshaw, J. Vac. Sci. Technol. ... Phys. Lett. 63,266 1 (1 993) 12. EC Boswell and P. R. Wilshaw, J. Vac. Sci. Technol. ...

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Research paper thumbnail of Nano planar coil actuated micro paddle resonator for mass detection

Microelectronic Engineering, 2011

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Research paper thumbnail of pH-dependent adsorption of Au nanoparticles on chemically modified Si 3 N 4 MEMS devices

Journal of Experimental Nanoscience, 2009

Microelectromechanical systems (MEMS) are devices that represent the integration of mechanical an... more Microelectromechanical systems (MEMS) are devices that represent the integration of mechanical and electrical components in the micrometer regime. Self-assembled monolayers (SAMs) can be used to functionalise the surface of MEMS resonators in order to fabricate chemically specific mass sensing devices. The work carried out in this article uses atomic force microscopy (AFM) and X-ray photoemission spectroscopy (XPS) data to investigate

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Research paper thumbnail of Simulation studies of Plasmon enchanced evanescent near-field optical lithography

Bookmarks Related papers MentionsView impact

Research paper thumbnail of FIB direct write of ALD A1203 mask for silicon DRIE

Bookmarks Related papers MentionsView impact

Research paper thumbnail of A quantitative comparison between helium ion and electron beam lithography on PMMA resist

Helium ion beam lithography (HIBL), an emerging technique that uses a sub-nanometre focused beam ... more Helium ion beam lithography (HIBL), an emerging technique that uses a sub-nanometre focused beam of helium ions to expose resist, has introduced an alternative to electron beam lithography (EBL) to extend beyond existing minimum feature sizes. HIBL has several advantages over EBL, including a higher patterning resolution due to a smaller spot size [1] and a reduced proximity effect due to low ion backscattering and deflection [2, 3]. However, there is yet to be a direct comparison of these two techniques on thin layer resists. Here, we present a quantitative and direct comparison study on EBL and HIBL with respect to sensitivity and proximity effects using poly(methyl methacrylate) (PMMA), an established benchmark EBL resist, leading to a demonstration of high resolution HIBL patterning of line arrays.

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Research paper thumbnail of Effects of focused ion beam dwell time on Nano fabrication

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Research paper thumbnail of Special issue on Nano Lithography 2013

Microelectronic Engineering, 2014

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Research paper thumbnail of Liquid-like behaviour of gold nanowire bridges

Applied Physics Letters, 2017

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Research paper thumbnail of Helium Ion Beam Lithography on Fullerene Molecular Resists for Sub-10 nm Patterning

Microelectronic Engineering, 2016

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Research paper thumbnail of Angular effects in focused ion beam milling of silicon

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Research paper thumbnail of Finite Element Study of a Micro-Opto-XRay Imaging Lens for Biomedical Applications

Micro-Electro-Opto-Mechanical-Systems or MOEMS have potential applications inter alia in biomedic... more Micro-Electro-Opto-Mechanical-Systems or MOEMS have potential applications inter alia in biomedical research. For instance, studies of the Bystander Effect require controlled irradiation of biological cells with focused X-rays to reveal the mechanisms occurring. X-ray focusing may be achieved using an adaptive optic micro-lens in which focusing is entirely reflective and therefore compatible with broad band illumination, an improvement over diffractive systems such as zone plates. Such a micro-lens can be microfabricated in the form of a bent-cantilever beam made from two dissimilar materials (polyimide and gold) in a thermal bimorph configuration, actuated with a micro heater. The parallel horizontal slots on the beam provide the transmission and focusing functions, while the heater provides control of the focal length through variation of the beam’s curvature. This novel system has been named 1D-MOXI (Micro-Opto-X-ray Imaging) and a basic system has already been made and tested thermo-mechanically. The present paper focuses on details of the geometry of the deformed slotted micro-beam lens element under thermally derived strain, using finite element analysis, and suggests an optimized MOEMS design, giving prescribed curvature of the lens through changing the number and the dimensions of the slots. The study reveals the localized stress and the small deviations of the micro-lens behavior from that of perfect spherical geometry. The focal length variation with temperature is compared with the experimental values and those predicted by an analytical model.

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Research paper thumbnail of Optimization of a novel micro-opto-X-ray imaging lens

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Micro/Nano X-Ray Tomography Reconstruction Tuning Using SEM Images for PEMFC Gas Diffusion Layers

X-ray micro/nano tomography is a powerful tool to reveal inside structures of a sample, either an... more X-ray micro/nano tomography is a powerful tool to reveal inside structures of a sample, either an IC chip or a porous material. A challenge in X-ray tomography is to select a correct threshold to ensure the reconstructed models as close to the reality as possible. This paper presents a study to use scanning electron microscope (SEM) images as references for

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Research paper thumbnail of 3D reconstruction of a micro pipette tip

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Research paper thumbnail of Characterisation of nanoporous materials using Focused Ion Beam milling method

ABSTRACT Focused Ion Beam (FIB) is generally used for machining of solid and bulk materials. Howe... more ABSTRACT Focused Ion Beam (FIB) is generally used for machining of solid and bulk materials. However, new applications such as FIB nanotomography of nanoporous surfaces require sputtering yield characterisation. This paper presents the study of the FIB sputtering yield of Ga+ on nanoporous catalyst layers (CL) of a polymer electrolyte fuel cell (PEFC) based on analytical calculations and SEM stereo imaging experiments. It is shown that a porosity of around 50% has a significant effect (approximately 400%) on the sputtering yield of materials.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Micro/nano X-ray tomography reconstruction fine-tuning using scanning electron microscope images

The use of scanning electron microscope (SEM) images as references for threshold tuning of X-ray ... more The use of scanning electron microscope (SEM) images as references for threshold tuning of X-ray micro/nano computed tomography reconstruction is proposed. In this research, high-resolution SEM images were used to provide a good estimation of the fibre diameter in the surface of gas diffusion layers (GDL) (5-10 mum). The X-ray tomography reconstructed binary images containing 3D information, including both the surface and the inside volume. Using the SEM images of a particular feature in carbon fibres, GDL layers were compared with the reconstructed surface of that feature from X-ray tomography data and provided the threshold estimation for reconstruction of the whole structure. Fibre diameter and continuity of the material from both the CT reconstruction and SEM images were analysed to obtain the optimum reconstruction. A linear relationship between fibre diameter and threshold variation has been found for micro/nano tomography of GDL layers.

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Research paper thumbnail of Embossing of 3D ceramic microstructures

Microsystem …, 2002

... Piezoceramics such as lead zirconate titanate (PZT) have been widely used in MEMS applica-tio... more ... Piezoceramics such as lead zirconate titanate (PZT) have been widely used in MEMS applica-tions. ... 2. The PMMA micro-moulds can be made by various existing methods such as LIGA (German acronym for X-ray lithography, electrodeposition Fig. ...

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Research paper thumbnail of Design and fabrication of a micro Wankel engine using MEMS technology

Microelectronic engineering, 2004

... Research Centre for Micro Engineering and Nano Technology, School of Engineering, The Univers... more ... Research Centre for Micro Engineering and Nano Technology, School of Engineering, The University of Birmingham, Edgbaston, Birmingham B15 2TT, UK. ... Conventional SU-8 processes often create a trench with wide top and narrow bottom, known as the T-shape, which is ...

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Research paper thumbnail of The focusing performance of an aperiodic double layer metallic grating

Microelectronic Engineering, 2014

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Enhanced field emission from polysilicon emitters using porous silicon

… , 1996. IVMC'96., …, 1996

... Sci. Technol. B 14, (1996), in press 6. SE Huq, M. Huang, PRWilshaw and P. D. Prewett, submit... more ... Sci. Technol. B 14, (1996), in press 6. SE Huq, M. Huang, PRWilshaw and P. D. Prewett, submitted to IVMC'96 7. EC Boswell, M. Huang, GDW Smith and PR Wilshaw, J. Vac. Sci. Technol. ... Phys. Lett. 63,266 1 (1 993) 12. EC Boswell and P. R. Wilshaw, J. Vac. Sci. Technol. ...

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Research paper thumbnail of Nano planar coil actuated micro paddle resonator for mass detection

Microelectronic Engineering, 2011

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Research paper thumbnail of pH-dependent adsorption of Au nanoparticles on chemically modified Si 3 N 4 MEMS devices

Journal of Experimental Nanoscience, 2009

Microelectromechanical systems (MEMS) are devices that represent the integration of mechanical an... more Microelectromechanical systems (MEMS) are devices that represent the integration of mechanical and electrical components in the micrometer regime. Self-assembled monolayers (SAMs) can be used to functionalise the surface of MEMS resonators in order to fabricate chemically specific mass sensing devices. The work carried out in this article uses atomic force microscopy (AFM) and X-ray photoemission spectroscopy (XPS) data to investigate

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