Semefab Scotland Ltd.

Glenrothes, United Kingdom

Semefab Scotland Ltd.

Glenrothes, United Kingdom

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Ashwell G.J.,Lancaster University | Ashwell G.J.,Bangor University | Phillips L.J.,Bangor University | Robinson B.J.,Lancaster University | And 13 more authors.
ACS Nano | Year: 2010

The highly doped electrodes of a vertical silicon nanogap device have been bridged by a 5.85 nm long molecular wire, which was synthesized in situ by grafting 4-ethynylbenzaldehyde via C-Si links to the top and bottom electrodes and thereafter by coupling an amino-terminated fluorene unit to the aldehyde groups of the activated electrode surfaces. The number of bridging molecules is constrained by relying on surface roughness to match the 5.85 nm length with an electrode gap that is nominally 1 nm wider and may be controlled by varying the reaction time: the device current increases from ≤1 pA at 1 V following the initial grafting step to 10-100 nA at 1 V when reacted for 5-15 min with the amino-terminated linker and 10 μA when reacted for 16-53 h. It is the first time that both ends of a molecular wire have been directly grafted to silicon electrodes, and these molecule-induced changes are reversible. The bridges detach when the device is rinsed with dilute acid solution, which breaks the imine links of the in situ formed wire and causes the current to revert to the subpicoampere leakage value of the 4-ethynylbenzaldehyde-grafted nanogap structure. © 2010 American Chemical Society.


Quaresma H.J.,University of Lisbon | Quaresma H.J.,Semefab Scotland Ltd | Dos Santos P.M.,University of Lisbon | Serra A.C.,University of Lisbon
Electronics Letters | Year: 2011

The effect of temperature on substrate coupling is reported for the first time. Modelling and experimental results are presented, showing a significant linear dependence of the substrate resistance with temperature in the range between 257 and 418K. The observed decrease in substrate resistance at lower temperatures implies that the substrate noise coupling could be seriously underestimated if the temperature effect is not taken into account. These results reveal the importance of including the effects of temperature on the substrate resistance models for the correct modelling of the substrate noise coupling. © 2011 The Institution of Engineering and Technology.


Grant
Agency: GTR | Branch: EPSRC | Program: | Phase: Research Grant | Award Amount: 5.00M | Year: 2013

Capsule endoscopy for medical diagnosis in the gastrointestinal (GI) tract has emerged only in the past 10 years. Now established in pillcams, which have benefitted more than 1 m patients worldwide, it is a clear candidate for further innovation. Most capsule endoscopy devices record and transmit video data representing the visual appearance of the inside of the gut, but work has begun on other diagnostic techniques, such as the measurement of pH, and there has been some research into the use of capsules for treatment as well. Medical ultrasound imaging is a safe, inexpensive technique which can be applied in real-time at the point of care. Ultrasound is also capable of treatment through focused ultrasound surgery and, in research, for targeted drug delivery. The core of the Sonopill programme is the exploration of ultrasound imaging and therapeutic capabilities deployed in capsule format. This will be supported by extensive pre-clinical work to demonstrate the complementary nature of ultrasound and visual imaging, along with studies of multimodal diagnosis and therapy, and of mechanisms to control the motion of the Sonopill as it travels through the GI tract. This brings research challenges and opportunities in areas including ultrasound device and systems design, microengineering and microelectronic packaging, autonomous capsule positioning, sensor suites for diagnosis and intervention, and routes to translation into clinical practice. Our carefully structured but open-ended approach maximises the possibility to meet these research challenges while delivering for the UK a sustainable international lead in multimodality capsule endoscopy, to provide greater capabilities for the clinician, more acceptable practice for the patient population, and lower costs for economic wellbeing.


Balachandran A.,University of Sheffield | Sweet M.,University of Sheffield | Ngwendson L.,University of Sheffield | Sankara Narayanan E.M.,University of Sheffield | And 3 more authors.
Proceedings of the International Symposium on Power Semiconductor Devices and ICs | Year: 2012

In this paper, we report the experimental results of a 3.3kV rated CIGBT (Clustered Insulated Gate Bipolar Transistor) with planar gates in non-punch through technology (NPT) with RTA anode. Previously it was reported that for identical turn-off losses the on-state voltage of the 3.3kV NPT-CIGBT is less than 0.7V as compared to that of a commercially available FS-IGBT. Herein we show that due to the low saturation current density, the CIGBT has a rugged short circuit performance, as measured to be of more than 100μs at 25°C which is much higher than any MOS controlled bipolar device ever reported. Furthermore, results also show that the use of the RTA anode compared to the diffused anode helps in reducing the turn-off losses by about 50% without affecting the Vce(sat) of the device. © 2012 IEEE.


Balachandran A.,University of Sheffield | Sweet M.R.,University of Sheffield | Luther-King N.,University of Sheffield | Narayanan E.M.S.,University of Sheffield | And 3 more authors.
IEEE Transactions on Electron Devices | Year: 2012

In this paper, we report the experimental results of a 3.3-kV-rated clustered insulated gate bipolar transistor (CIGBT) with planar gates in nonpunchthrough technology (NPT) and rapid thermal annealing (RTA) anode. Previously, it had been shown that, for identical turn-off losses, the on -state voltage of the 3.3-kV CIGBT is more than 0.7 V lower than that of an equivalent IGBT. Herein, we show that, due to the low saturation current density, the CIGBT has a rugged short-circuit performance of more than 10 $\mu\hbox{s even at 125 $C. Furthermore, results also show that the use of the RTA anode, as compared with, the diffused anode helps in reducing the turn-off losses by about 50% without affecting the V \rm ce(sat) value of the device. © 2012 IEEE.

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