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Douglas Macintyre

Bio: Douglas Macintyre is an academic researcher from University of Glasgow. The author has contributed to research in topics: Resist & Electron-beam lithography. The author has an hindex of 20, co-authored 77 publications receiving 1422 citations.


Papers
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Journal ArticleDOI
M. Gnan1, Stephen Thoms1, Douglas Macintyre1, R.M. De La Rue1, Marc Sorel1 
TL;DR: Fully etched photonic wires in silicon-on-insulator have been fabricated and propagation loss values as low as 0.92 plusmn 0.14 dB/cm have been obtained.
Abstract: Fully etched photonic wires in silicon-on-insulator have been fabricated and propagation loss values as low as 0.92 plusmn 0.14 dB/cm have been obtained. Hydrogen silsesquioxane (HSQ) was used as an electron beam resist and as a direct mask in the dry-etch processing of the silicon core layer. The dimensional repeatability of the fabrication process was also estimated through measurements of the wavelength selection performance of nominally identical photonic wire Bragg gratings fabricated at intervals over a period of 37 days.

221 citations

Journal ArticleDOI
TL;DR: In this article, the authors presented a metal-gate high-k-dielectric enhancement-mode (e-mode) III-V MOSFET with the highest reported effective mobility and transconductance to date.
Abstract: We present metal-gate high-k-dielectric enhancement-mode (e-mode) III-V MOSFETs with the highest reported effective mobility and transconductance to date. The devices employ a GaGdO high-k (k = 20) gate stack, a Pt gate, and a delta-doped InGaAs/AlGaAs/GaAs hetero-structure. Typical 1-mum gate length device figures of merit are given as follows: saturation drive current, Id,sat = 407 muA/mum; threshold voltage, Vt = +0.26 V; maximum extrinsic transconductance, gm = 477 muS/mum (the highest reported to date for a III-V MOSFET); gate leakage current, Ig = 30 pA; subthreshold swing, S = 102 mV/dec; on resistance, Ron = 1920 Omega-mum; Ion/Ioff ratio = 6.3 x 104; and output conductance, gd = 11 mS/mm. A peak electron mobility of 5230 cm2/V. s was extracted from low-drain-bias measurements of 20 mum long-channel devices, which, to the authors' best knowledge, is the highest mobility extracted from any e-mode MOSFET. These transport and device data are highly encouraging for future high-performance n-channel complementary metal-oxide-semiconductor solutions based on III-V MOSFETs.

172 citations

Journal ArticleDOI
TL;DR: In this paper, an electron beam lithographic tool with focussed Gaussian beam was used to define shapes directly for cellular engineering applications, and the effect of deflection aberrations across the writing field was investigated.

111 citations

Journal ArticleDOI
TL;DR: In this paper, the authors presented results of the first ever THz submicron planar planar Gunn diode fabricated in In0.53Ga0.47As on an InP substrate, operating at a fundamental frequency above 300 GHz.
Abstract: The length of the transit region of a Gunn diode determines the natural frequency at which it operates in fundamental mode—the shorter the device, the higher the frequency of operation. The long-held view on Gunn diode design is that for a functioning device the minimum length of the transit region is about 1.5 μm, limiting the devices to fundamental mode operation at frequencies of roughly 60 GHz. Study of these devices by more advanced Monte Carlo techniques that simulate the ballistic transport and electron-phonon interactions that govern device behaviour, offers a new lower bound of 0.5 μm, which is already being approached by the experimental evidence that has shown planar and vertical devices exhibiting Gunn operation at 600 nm and 700 nm, respectively. The paper presents results of the first ever THz submicron planar Gunn diode fabricated in In0.53Ga0.47As on an InP substrate, operating at a fundamental frequency above 300 GHz. Experimentally measured rf power of 28 μW was obtained from a 600 nm long × 120 μm wide device. At this new length, operation in fundamental mode at much higher frequencies becomes possible—the Monte Carlo model used predicts power output at frequencies over 300 GHz.

62 citations

Proceedings ArticleDOI
01 Jan 2007
TL;DR: In this article, a review of the development of III-V MOSFETs with high mobility channels is presented, and the authors discuss properties of the GdGaO/ Ga2O3 MOS systems, present GaAs MOS-FET DC and RF data, and conclude with an outlook for high indium content channel MOS FETs.
Abstract: Developments over the last 15 years in the areas of materials and devices have finally delivered competitive III-V MOSFETs with high mobility channels. This paper briefly reviews the above developments, discusses properties of the GdGaO/ Ga2O3 MOS systems, presents GaAs MOSFET DC and RF data, and concludes with an outlook for high indium content channel MOSFETs. GaAs based MOSFETs are potentially suitable for RF power amplification, switching, and front-end integration in mobile and wireless applications while MOSFETs with high indium content channels are of interest for future CMOS applications.

59 citations


Cited by
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Journal ArticleDOI
TL;DR: The use of nanoscale disorder is demonstrated to stimulate human mesenchymal stem cells (MSCs) to produce bone mineral in vitro, in the absence of osteogenic supplements, which has implications for cell therapies.
Abstract: A key tenet of bone tissue engineering is the development of scaffold materials that can stimulate stem cell differentiation in the absence of chemical treatment to become osteoblasts without compromising material properties. At present, conventional implant materials fail owing to encapsulation by soft tissue, rather than direct bone bonding. Here, we demonstrate the use of nanoscale disorder to stimulate human mesenchymal stem cells (MSCs) to produce bone mineral in vitro, in the absence of osteogenic supplements. This approach has similar efficiency to that of cells cultured with osteogenic media. In addition, the current studies show that topographically treated MSCs have a distinct differentiation profile compared with those treated with osteogenic media, which has implications for cell therapies.

2,249 citations

Journal ArticleDOI
TL;DR: An overview of the current state-of-the-art in silicon nanophotonic ring resonators is presented in this paper, where the basic theory of ring resonance is discussed and applied to the peculiarities of submicron silicon photonic wire waveguides: the small dimensions and tight bend radii, sensitivity to perturbations and the boundary conditions of the fabrication processes.
Abstract: An overview is presented of the current state-of-the-art in silicon nanophotonic ring resonators. Basic theory of ring resonators is discussed, and applied to the peculiarities of submicron silicon photonic wire waveguides: the small dimensions and tight bend radii, sensitivity to perturbations and the boundary conditions of the fabrication processes. Theory is compared to quantitative measurements. Finally, several of the more promising applications of silicon ring resonators are discussed: filters and optical delay lines, label-free biosensors, and active rings for efficient modulators and even light sources.

1,989 citations

Journal ArticleDOI
TL;DR: In this paper, the basic principles of nano-printing are discussed, with an emphasis on the requirements on materials for the imprinting mold, surface properties, and resist materials for successful and reliable nanostructure replication.
Abstract: Nanoimprint lithography (NIL) is a nonconventional lithographic technique for high-throughput patterning of polymer nanostructures at great precision and at low costs. Unlike traditional lithographic approaches, which achieve pattern definition through the use of photons or electrons to modify the chemical and physical properties of the resist, NIL relies on direct mechanical deformation of the resist material and can therefore achieve resolutions beyond the limitations set by light diffraction or beam scattering that are encountered in conventional techniques. This Review covers the basic principles of nanoimprinting, with an emphasis on the requirements on materials for the imprinting mold, surface properties, and resist materials for successful and reliable nanostructure replication.

1,644 citations

Journal ArticleDOI
TL;DR: The 2017 roadmap of terahertz frequency electromagnetic radiation (100 GHz-30 THz) as discussed by the authors provides a snapshot of the present state of THz science and technology in 2017, and provides an opinion on the challenges and opportunities that the future holds.
Abstract: Science and technologies based on terahertz frequency electromagnetic radiation (100 GHz–30 THz) have developed rapidly over the last 30 years. For most of the 20th Century, terahertz radiation, then referred to as sub-millimeter wave or far-infrared radiation, was mainly utilized by astronomers and some spectroscopists. Following the development of laser based terahertz time-domain spectroscopy in the 1980s and 1990s the field of THz science and technology expanded rapidly, to the extent that it now touches many areas from fundamental science to 'real world' applications. For example THz radiation is being used to optimize materials for new solar cells, and may also be a key technology for the next generation of airport security scanners. While the field was emerging it was possible to keep track of all new developments, however now the field has grown so much that it is increasingly difficult to follow the diverse range of new discoveries and applications that are appearing. At this point in time, when the field of THz science and technology is moving from an emerging to a more established and interdisciplinary field, it is apt to present a roadmap to help identify the breadth and future directions of the field. The aim of this roadmap is to present a snapshot of the present state of THz science and technology in 2017, and provide an opinion on the challenges and opportunities that the future holds. To be able to achieve this aim, we have invited a group of international experts to write 18 sections that cover most of the key areas of THz science and technology. We hope that The 2017 Roadmap on THz science and technology will prove to be a useful resource by providing a wide ranging introduction to the capabilities of THz radiation for those outside or just entering the field as well as providing perspective and breadth for those who are well established. We also feel that this review should serve as a useful guide for government and funding agencies.

1,068 citations

01 Jan 1999
TL;DR: Damascene copper electroplating for on-chip interconnections, a process that was conceived and developed in the early 1990s, makes it possible to fill submicron trenches and vias with copper without creating a void or a seam and has thus proven superior to other technologies of copper deposition as discussed by the authors.
Abstract: Damascene copper electroplating for on-chip interconnections, a process that we conceived and developed in the early 1990s, makes it possible to fill submicron trenches and vias with copper without creating a void or a seam and has thus proven superior to other technologies of copper deposition. We discuss here the relationship of additives in the plating bath to superfilling, the phenomenon that results in superconformal coverage, and we present a numerical model which accounts for the experimentally observed profile evolution of the plated metal.

1,006 citations