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New Publications are available now online for this publication.
Please follow the links to view the publication.Gaussian process regression for virtual metrology of plasma etch
http://dl-live.theiet.org/content/conferences/10.1049/cp.2010.0485
Plasma etch is a complex semiconductor manufacturing process in which material is removed from the surface of a silicon wafer using a gas in plasma form. As the process etch rate cannot be measured easily during or after processing, virtual metrology is employed to predict the etch rate instantly using ancillary process variables. Virtual metrology is the prediction of metrology variables using other easily accessible variables and mathematical models. This paper investigates the use of Gaussian process regression as a virtual metrology modelling technique for plasma etch data.A novel soft-switching boost power factor correction converter with an active snubber
http://dl-live.theiet.org/content/conferences/10.1049/cp.2010.0055
In this paper, a novel soft switching transition technique in power factor correction (PFC) 1-Φ AC-DC converter operating in a continuous conduction mode (CCM) with fixed switching frequency is presented. All of the semiconductor devices of the proposed converter are turned on and off under exact or near zero voltage switching and/or zero current switching. No additional voltage and current stresses on the main switch and main diode occur. The operating modes and analysis for the proposed converter are explained. To evaluate the performance of the suggested converter, simulation results for a 400V, 500W 1-phase AC-DC converter are presented. The simulated results confirm that the converter operates at almost unity power factor with reduced switching losses in a proposed converter. The output voltage is regulated without affecting zero voltage switching even under step change in input voltage. (6 pages)High-power GaAs photoconductive semiconductor switch triggered with picosecond laser pulse
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.1637
In order to generate ultrafast electrical pulse by using photoconductive semiconductor switch (PCSS), a switch with a gap of 14 mm was fabricated from semi-insulating GaAs. Illuminated by laser pulse at wavelength of 1064 nm and 532 nm, photoconductivity tests of the PCSS were performed at different bias voltages. Preliminary experimental results suggest that the rise time of the current through the PCSS is significantly reduced when triggered by picosecond laser pulse. The experimental results with different optical energy are presented and discussed. (3 pages)High power reverse conducting solid state closing switch for environmental applications
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.1651
The presentation will discuss the specification, the design, the construction and the test results of a solid state switch which is used in De-NOx/De-SOx modulators. The closing switch is operating at a charge voltage of 20 kVdc with a 300 Hz pulse repetition rate and a 12.6 kA, 12 μs exponential decay waveform. In case of arcing in the load the waveform will change to a 250 μs damped sine wave. The current rise rate is in access of 10 kA/μs or more. The paper will show the selection criteria of the semiconductor devices, and the optimization of the devices for this application. The complete ready-to-use switch is built-up with a series connection of eight reverse conducting devices with individual driver units which are optical triggered. This construction results in compact stack with very low self inductance. The switch is capable to operate continuous at a pulse repetition rate of 300 Hz and can be cooled by transformer oil or de-ionized water. Information will also be given on reliability and life expectancy based on tests and earlier produced switches. (4 pages)New methods and techniques used by design software and IP suppliers to increase design productivity
http://dl-live.theiet.org/content/conferences/10.1049/ic.2008.0761
This paper presents the following: semiconductor devices, a need for programmable platforms; changing need of design tools and IPs for programmable platforms; and SoftJin's offerings to programmable platform developers. Reconfiguration granularity: coarse and fine grain, and application driven reconfigurable devices are also discussed. (30 pages)Development of a sensing seat for human authentication
http://dl-live.theiet.org/content/conferences/10.1049/cp_20070412
In this work the development of a sensing seat for human authentication is reported. Such a system can be used in all the critical scenarios where a seat is available to the human subject. In order to face the authentication task, the sensing seat was developed by means of a novel unobtrusive sensing technology. This is mainly due to two aspects: the unavailability of an existing sensing seat system for human authentication and the inadequacy of the existing sensor technology in order to address the human subject recognition as well as the integration of the sensors in the seat. Thanks to the development of a redundant sensor network, we adopted a hierarchical architecture. Three cooperating classifiers (a distance-based classifier, a KSOM and a MLP) shares the input data and supplying three different classification results. A final classifier (a weighted averager) performs the fusion of the results and supplies the final response.Study on the continuous quality improvement systems in semiconductor assembly
http://dl-live.theiet.org/content/conferences/10.1049/cp_20060734
Compared with other manufacturing processes, the process of semiconductor assembly has several particular characteristics: highly automated manufacturing processes, high manufacturing speed and multivariate critical quality characteristics. Based on the requirements of continuous quality improvement in semiconductor assembly processes, a method of material quality tracking and controlling with SPC chart was put forward. With this method, the sampling program can be adjusted according to the quality record of a supplier. And then a framework of 3-layer SPC was put forward. In this framework, the CTQ, qualification rate of processes, and qualification rate of final products can be controlled by proper SPC chart in different layer and this method is helpful to avoid unqualified products effectively. Furthermore, a model of quality improvement in semiconductor assembly with SPC and data mining was studied. This model can be used for improving the ability of process diagnosing and shortening the diagnosing time. At last, a structure of an integrated quality information system for semiconductor assembly was put forward. The result of this paper may be helpful for the continuous quality improvement in semiconductor assembly processes and it can also be used in other similar processes.Semiconductors + software: the fuel of the modern economy (Abstract only)
http://dl-live.theiet.org/content/conferences/10.1049/cp_20062254
Since the birth of the transistor in 1947 semiconductor technology has seen a rapid rate of development, leading to a vast diversity of applications. Today's integrated circuits can now contain up to a billion transistors and provide the fuel for the Digital Information Age which so seamlessly affects all of our lives and touches billions of people on our planet. Today's technology is "embedded" or hidden in applications such as mobile phones, digital cameras, information appliances, control systems, automotive electronics with the digital systems of today doing the work of mechanical systems of the past. The software content of many systems is now more costly than the metal out of which they are built. With the opposing forces of added complexity with increasing pressure to shorten time to market, the semiconductor industry has reached a level of maturity that has caused horizontal specialist companies to emerge with a theme of global teamwork being necessary for success. Sir Robin Saxby will give a brief history of the semiconductor industry, highlighting the new challenges and applications as we look toward 2020. He will touch on the way in which our power networks have embraced the advancement of control systems in power distribution. He will also discuss how developments in this field have given rise to more powerful yet more power efficient and lower cost devices. (1 page)Quantum dots and their potential applications: Nanoco - the story of a still nascent company
http://dl-live.theiet.org/content/conferences/10.1049/ic_20050015
This paper is a powerpoint presentation on the potential applications of quantum dots such as in authentication systems, LEDs, displays, solar cell concentrators and other electronic devices, and in life sciences as in diagnostics, biological screening, and microscopy. The presentation includes a brief background on Nanoco Technologies Ltd., a UK organization established to commercialize unique, proprietary and widely patented methods of synthesizing quantum dots. The presentation also discusses the optical qualities of semiconductor nanoparticles and the various advantages of using quantum dots.Process Technology for Silicon Carbide Devices
http://dl-live.theiet.org/content/books/cs/pbep002e
<p xmlns="http://pub2web.metastore.ingenta.com/ns/">This book explains why SiC is so useful in electronics, gives clear guidance on the various processing steps (growth, doping, etching, contact formation, dielectrics etc) and describes how these are integrated in device manufacture. The book should serve as an advanced tutorial and reference for those involved in applying the very latest technology emerging from university and commercial laboratories around the world.</p>Strained Silicon Heterostructures: materials and devices
http://dl-live.theiet.org/content/books/cs/pbcs012e
<p xmlns="http://pub2web.metastore.ingenta.com/ns/">This book comprehensively covers the areas of materials growth, characterisation and descriptions for the new devices in silicon-heterostructure, material systems.</p>Power electronics reliability in rail traction
http://dl-live.theiet.org/content/conferences/10.1049/ic_19980075
Power electronics, as applied to the traction package, has thus grown from (usually a pair of) straightforward bridge rectifiers with no controls, through thyristor bridges and choppers controlled with analogue electronics, to microprocessor controlled, GTO based variable voltage-variable frequency inverters fed from (microprocessor controlled, GTO based) 4-quadrant power converters and incorporating a (microprocessor controlled, GTO based) rheostatic braking chopper. This represents a significant increase in the number of power semiconductors used in traction control, along with a huge increase in the complexity of the controlling circuitry, admittedly against a desire for improved performance both in terms of function and cost of ownership. In considering the rate of failures and their effects on service, this substantial increase in the number of devices and associated control electronics should be taken into account. (7 pages)Power semiconductor devices in pulsed power applications
http://dl-live.theiet.org/content/conferences/10.1049/ic_19970425
Power semiconductors-diodes, thyristors, insulated gate bipolar transistors (IGBTs) and GTOs-are key components in pulsed power applications in the SUBT/FP-EC sections of CERN. This paper mentions these types of semiconductor devices available today and mentions future developments. Since the subject is very large, the physics of the devices are not be discussed in detail but more attention is paid to an overview concerning the device properties and applications in the pulse power circuits at CERN. (5 pages)Discrete event simulation in a semiconductor assembly area
http://dl-live.theiet.org/content/conferences/10.1049/cp_19970142
This paper discusses a simulation experience in semiconductor assembly manufacturing areas. Much research on semiconductor wafer fabrication and final test areas has been active, however, not much research has been done in a semiconductor assembly area. Because of its characteristics of mass production and the stochastic nature of simulation, practical application of simulation to the semiconductor assembly area has many problems. In this paper we present an analysis of manufacturing performances in a specific semiconductor assembly area.Transient thermal impedance measurement in power semiconductor devices
http://dl-live.theiet.org/content/conferences/10.1049/ic_19960860
This paper first examines the method widely used by semiconductor manufacturers to generate the transient thermal response curves. It then goes on to examine the validity of such curves by means of measuring the die temperature rise under pulsed power conditions using an infrared camera and by generating a comprehensive thermal model of the semiconductor device and package. The results are finally presented and conclusions are made. (6 pages)Power electronic devices and their impact for power transmission
http://dl-live.theiet.org/content/conferences/10.1049/cp_19960365
The use of power semiconductor devices in the transmission of electrical power is at once well established and growing rapidly. HVDC transmission is an established technology for which the thyristor has become the workhorse since the installation of the first solid-state power convertor at Eel River in 1972. For improving the utilisation of AC networks and the quality of the supply of AC power, flexible AC transmission systems (FACTS) technology can be utilised. FACTS equipment based on thyristors, e.g. the static VAr compensator (SVC), are now well established, whilst others, requiring fully controllable (bimodal) power electronic devices, are under development. Examples include the advanced static compensator (STATCOM), the unified power flow controller (UPFC) and the active filter. Additionally, power integrity may be reinforced by drawing from a reservoir of energy, for example a superconducting magnetic energy store (SMES), requiring access via power electronic convertors.Automatic transistor lead inspection
http://dl-live.theiet.org/content/conferences/10.1049/cp_19950693
This paper has described the development of a system for real-time inspection of transistor leads in a production environment. The system has been introduced into a factory in prototype form. This uses a transputer-based image processing system housed in an industrial PC and has given five months operational experience. Cost and other considerations require the production of an embedded system which will form part of the taping machine instrumentation and control system.Methods of measurement to assess the suitability of materials for the control of static electricity
http://dl-live.theiet.org/content/conferences/10.1049/ic_19950415
Static electricity presents risks of damage to semiconductor devices in manufacture, circuit board building, handling and servicing. It presents risks to the microelectronic systems through data corruption and operational upset from static discharges. The various ways that the characteristics of materials are relevant to these risks are noted and methods used to assess these characteristics are outlined. (6 pages)Radiation effects on advanced bipolar and MOS devices
http://dl-live.theiet.org/content/conferences/10.1049/ic_19950183
This paper describes the effects of gamma radiation on modern bipolar and MOS semiconductors, as experienced in typical nuclear power industry applications. The environmental conditions under which components and equipment have to operate are reviewed and the influence of these on microelectronic devices is considered. Special emphasis is placed upon the recent generation of radiation tolerant processes. (7 pages)A three-phase to DC converter combining controlled step-down of voltage and bi-directional power flow
http://dl-live.theiet.org/content/conferences/10.1049/cp_19940980
A new configuration for a three-phase bi-directional power converter (AC-DC and DC-AC) is presented. The converter is operated as a step-down converter where the output voltage can be controlled in the range of 0 to 1.5 V̂<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">ph</sub>. The power switch configuration is simpler than the conventional anti-parallel bridge used for bi-directional step-down rectification. It has nine controllable switches and twelve diodes. In the rectifier and inverter mode, line current can be sinusoidally regulated with unity displacement factor. This complies with the EN standard on harmonic currents. Synchronous PWM is implemented in a field programmable gate array and regulation of the output is achieved with a PID controller. Simulation and experimental results are provided to demonstrate the effectiveness of the proposed converter system.Control of the three phase AC/DC transistor converter with quasi-resonant commutating circuit
http://dl-live.theiet.org/content/conferences/10.1049/cp_19941040
The aim of this paper is to present a system of control of AC/DC transistor power converters absorbing only active power from the AC source. In order to achieve sinusoidal source currents without increasing the transistors' power losses, the authors propose a method of power converter control minimizing the number of the transistors' switching and a simple quasi-resonant circuit to help the transistors' commutation process. Experiments on a laboratory prototype confirm the good performance of this simple control system.Fault-resistant scheme for transmission of control and status signals in high-power inverters via optical fibres
http://dl-live.theiet.org/content/conferences/10.1049/cp_19940998
In high power electronic equipment, control signals are often transmitted to the power semiconductors via fibre optic links. The standard signal code on the optical fibre is simple “light: semiconductor on, no light: semiconductor off”. If this code is used, transmission faults on the fibre optic link lead to uncontrolled switching of the power semiconductors. In contrast to the conventional code the described advanced transmission scheme achieves a high level of fault tolerance. In case of transmission faults it is able either to regenerate the correct signal or to switch the semiconductor controllably to a safe state. The advanced scheme applies known methods from communications theory innovatively to systems used in power electronics. The binary control signal is spread with a Barker sequence. The received signal is decoded with a correlation receiver. However, the described spread spectrum transmission system needs a higher bandwidth than the standard system, that can be interpreted as a drawback. Implementation on one ASIC per transceiving station is feasible.Control of a single-switch three-phase rectifier operating in continuous conduction mode
http://dl-live.theiet.org/content/conferences/10.1049/cp_19940981
In many power electronics power supplies, power converters connected to the network are diodes or thyristors bridges, which cause a great deal of harmonic currents. The increasing number of power converters used today may lead to high harmonic levels on the network, which is deemed a potential problem for electricity supply quality and the proper operation of electrical equipment. This explains the appearance of standards aimed at reducing the harmonic emission of power supplies. In terms of the three-phase power converters which are typical of medium- and high-power applications, the PWM rectifier is a well-known and efficient way of obtaining a good power factor. It is expensive, however, and the challenge is now to find more economical devices which would help the spread of such nonpolluting power converters. In response, this paper thus describes a single-switch, three-phase PWM rectifier. This power converter operates in continuous conduction mode in order to avoid the voltage or current overloads which are inherent to discontinuous conduction mode operation.The GEC Research Laboratories 1919-1984
http://dl-live.theiet.org/content/books/ht/pbht010e
<p xmlns="http://pub2web.metastore.ingenta.com/ns/">Covering the activities of the GEC Research Laboratories from 1919 until their end in 1984, this book includes sections on the original organisation and philosophy behind the laboratories, a decade by decade summary of the work, and specialist chapters focussing on such areas as lamps and lighting, valves, communications and semiconductors.</p>Analysis and implementation of space-vector-modulated three-phase matrix converter
http://dl-live.theiet.org/content/journals/10.1049/iet-pel.2012.0014
This study introduces a detailed analysis, design and implementation of a three-phase matrix converter based on space-vector modulation technique. The modulation strategy is described and modelled. All steps of hardware design using discrete semiconductor devices are given. The modulator is implemented using a digital signal processor. The experimental results for passive loading and three-phase induction motor conditions are given. Then the converter performance is discussed.PAD capacitance nulling circuit for QWIP-ROIC hybridisation
http://dl-live.theiet.org/content/journals/10.1049/el.2012.2853
A PAD capacitance nulling circuit has been investigated to be used in quantum-well infrared photodetector to read-out integrated circuit (QWIP-ROIC) hybridisation. Simulation results show that it is possible to cancel the parasitic capacitance of an analogical PAD in the specific range of detection of a QWIP (outputs from 0.2 to 13 nA). For the same QWIP-ROIC interface, the voltage was found to vary approximately 0.24 mV (0.008%) as opposed to 120 mV when the circuit is not used. Even though the presented circuit has been designed for this specific application, it shows great potential to be employed in all circuits where the input signal is a current and parasitic capacitances in the path of the signal are undesired.Zero-voltage transition–zero-current transition pulsewidth modulation DC–DC buck converter with zero-voltage switching–zero-current switching auxiliary circuit
http://dl-live.theiet.org/content/journals/10.1049/iet-pel.2011.0304
In this study, a new zero-voltage transition (ZVT)–zero-current transition (ZCT) quasi-resonant buck converter, which ensures zero crossings at any time required for soft switching (SS) and provides ZVT turn-on and ZCT turn-off together for the main switch of active snubber cell in buck converter is presented. The proposed circuit combines the most of the advantageous features of the circuits presented previously and overcomes most of drawbacks of these circuits by using only one auxiliary switch with fewer other components. Consequently, new ZVT–ZCT quasi-resonant buck converter, which is verified by a prototype of a 0.4-kW and 100-kHz circuit, is analysed in detail. All semiconductor devices operate under SS, the main switch is subjected to no additional voltage and current stresses, and the stress on the auxiliary switch is very low in the proposed new converter.Offset-voltage compensation for accurate current-source circuit
http://dl-live.theiet.org/content/journals/10.1049/el.2012.0739
The offset-voltage compensation technique is proposed for an accurate current-source circuit. This current source is made of a transistor, a resistor, and operational amplifier feedback in order to achieve a high output resistance as well as high accuracy of a generated current signal. Discrepancy from the ideal value mainly results from the offset voltage of the operational amplifier. The transconductance amplifier is utilised with a feedback loop that is controlled by the switched-capacitor integrator. The proposed technique is incorporated in the light-emitting diode driver circuit applications and successfully verified with hardware measurement.Novel commutation technique of AC–AC converters
http://dl-live.theiet.org/content/journals/10.1049/ip-epa_19981869
The AC–AC converter called the matrix converter is very simple in structure and has powerful controllability. However, to date there have been few practical applications, especially in power electronics fields. One of the major reasons is the commutation problem. The paper proposes a novel commutation technique which is very simple to implement. This commutation scheme allows the dead time to avoid current spikes of nonideal switches and at the same time establishes a current path of the inductive load to avoid voltage spikes. Experimental results obtained on a 5 kW prototype are discussed.Optimised input filter design and low-loss switching techniques for a practical matrix converter
http://dl-live.theiet.org/content/journals/10.1049/ip-epa_19970863
The matrix converter permits frequency conversion in a single-stage process. The perceived disadvantage of the matrix converter is that conduction losses are high. However, semisoft current commutation and optimal sequence switching can be used to minimise commutation losses so that at high switching frequencies the total losses in the matrix converter can be less than those in a conventional rectifier–inverter combination. The viability of the matrix converter depends to a large extent on the size and cost of the input filter components required to meet international power quality standards. In the paper filter designs are examined and guidelines established. Practical tests have been carried out on a 3.5 kW converter to validate computer models. It is concluded that the matrix converter is viable if the right combination of semiconductor switching techniques and input filter design are employed.Efficient testing and diagnosis of faulty power switches in SOCs
http://dl-live.theiet.org/content/journals/10.1049/iet-cdt_20060147
The use of power switches in modern system chips (SOCs) is inevitable as they allow for efficient on-chip static power management. Leakage is one of the main hurdles in low-power applications. Power switches enable power gating functionality, that is one or more parts of the SOC can be powered-off during standby mode thus leading to savings in the SOC's overall power consumption. To this end, a circuit and a method to test power switch is presented. The proposed method allows for the testing of on/off functionality. In case of segmented power switches, individual failing segments can be identified by using the proposed test strategy. The method only requires a small number of test patterns that are easy to generate. Furthermore, the proposed method is very scalable with the number of power switches and has a very small area-overhead.Editorial: Computers and Devices for Communication (CODEC 04)
http://dl-live.theiet.org/content/journals/10.1049/ip-cds_20059073
Delay bounds based constraint distribution method
http://dl-live.theiet.org/content/journals/10.1049/ip-cdt_20050026
Transistor sizing is one of the easiest post-processing transforms used to optimise critical paths to fill timing specifications. Most transistor sizing tools, based on nonlinear mathematical programs present high execution times and do not give an indication of the design space explored by the optimisation step. A fast transistor sizing method to address the problem of delay constraint distribution on a CMOS combinatorial path is defined. This method is based on a closed form model of the propagation delay that incorporates the effect of input slew rates on gate delays. The design space is characterised with a technique that allows the determination of the feasible delay bounds of any combinational paths. Then two different constraint distribution methods are defined that are compared to the equal delay distribution and to an industrial tool based on the Newton-Raphson-like algorithm. Validation is obtained on a 0.25 µm process by comparing the different constraint distribution techniques on various benchmarks.Carbon nanotube technology for solid state and vacuum electronics
http://dl-live.theiet.org/content/journals/10.1049/ip-cds_20040408
The authors demonstrate the fabrication of solid state and vacuum electronic devices using carbon nanotubes as the active channel and emitters. Single wall and multiwall carbon nanotubes (CNT) are deposited directly on substrates using chemical vapour deposition (CVD) and plasma enhanced chemical vapour deposition (PECVD), respectively. The fabrication of top gate and side gate field effect transistors is demonstrated using single wall CNTs. Vertically aligned multiwall CNTs are used to fabricate field emitter arrays or micro-gated field emitters, which have potential application in field emission displays, microwave amplifiers or electron guns.Low-power high‐speed performance of current-mode logic D flip-flop topology using negative-differential-resistance devices
http://dl-live.theiet.org/content/journals/10.1049/iet-cds_20070135
The low-power/high-speed performance of current-mode logic (CML) D flip-flops based on negative-differential-resistance (NDR) devices is presented. The device count used in the fabricated circuit has been significantly reduced by using the NDR-based D flip-flop topology, leading to enhanced low-power/high-speed performance. The operation of the fabricated NDR-based CML D flip-flop has been confirmed to 36 Gb/s, which is the highest speed among NDR-based differential‐mode D flip-flops reported to date. The power consumption of the D flip-flop core circuit was measured to be as low as 20 mW at a power supply voltage of −3.3 V. In addition, a power–delay product of 0.55 pJ has been obtained from the NDR-based CML D flip-flop, which is the lowest value to the authors' knowledge among the previously reported D flip-flops up to operation speeds in the region of 40 Gb/s.Editorial: Amorphous and microcrystalline semiconductors
http://dl-live.theiet.org/content/journals/10.1049/ip-cds_20030826
Fabrication of nanoscale device using individual colloidal gold nanoparticles
http://dl-live.theiet.org/content/journals/10.1049/ip-cds_20040957
A simple technique is presented for the fabrication of nanoscale devices. Commercially available bare gold colloidal nanoparticles are first trapped between two prefabricated large gap electrodes to form a metallic bridge by the application of an AC electric field. The nanoparticle bridge is then broken by slowly ramping a DC voltage across the junction until the current drops to zero. This simple, highly reliable and reproducible technique consistently produces metallic electrodes with less than 10 nm gap and can be applied to prefabricated electrodes up to 1 μm separation. The nanogaps created are ideally suited to contacting individual nanostructures. The paper describes an electrical transport study of a thiol coated 3 nm gold nanoparticle that shows a clear Coulomb staircase.Towards individual molecules as electronic components
http://dl-live.theiet.org/content/journals/10.1049/ip-cds_20040990
The goal of electronic functionality within an individual organic molecule was set many decades ago, but achieving it has not been straightforward. The simple combining rules of chemistry allow an unlimited variety of structures, and it has not been clear which are worth pursuing. It has also not been clear how it might be possible to assemble well-defined nanostructures of usable complexity. While the first steps along this road have required the development of new concepts and have been painfully slow, several milestones have now been passed. The confusion surrounding conduction through ultrathin layers has now been resolved, and stable low-defect two-terminal devices have now been fabricated in which the dominant charge transport is demonstrably through the electroactive organic molecules. Results obtained from these nanostructures will provide basic information about charge transport mechanisms on the molecular scale that will be vital for the future design of high-performance electronic components.Editorial: Noise in devices and circuits
http://dl-live.theiet.org/content/journals/10.1049/ip-cds_20040556
Scanning tunnelling optoelectronic microscope with 2 ps time resolution
http://dl-live.theiet.org/content/journals/10.1049/el_19961162
The authors have developed a scanning tunnelling optoelectronic microscope (STOEM) and measured electric pulses with a 2.5 ps width corresponding to a time resolution better than 2 ps. This substantial improvement was realised using low temperature-grown GaAs (LT-GaAs) for the photoconductive semiconductor switch (PCSS) on the probe and by reducing the probe dimension.Using body biasing to control phase-noise of CMOS <i xmlns="http://pub2web.metastore.ingenta.com/ns/">LC</i> oscillators
http://dl-live.theiet.org/content/journals/10.1049/el.2011.3739
An approach to adjusting and optimising the phase-noise performance of CMOS <i xmlns="http://pub2web.metastore.ingenta.com/ns/">LC</i> oscillators is presented. The technique is based on controlling the bulk-source voltage of the cross-coupled transistors in the oscillator core. It is shown that the impedance in the path of the current through the oscillator core to ground at the second harmonic of oscillation can be maximised through changing the value of the parasitic capacitances. The technique is validated by measured results from a proof-of-concept <i xmlns="http://pub2web.metastore.ingenta.com/ns/">LC</i> oscillator fabricated in a 90 nm CMOS process.Suppressing long tail in impulse response of MSM photodetectors using slow hole current subtraction
http://dl-live.theiet.org/content/journals/10.1049/el_20070982
Metal-semiconductor-metal (MSM) photodetectors with three contacts are proposed for subtracting slow hole currents for a shorter impulse response. The long tail, due to these slow holes, was eliminated using an MSM photodetector with three contacts. The measured FWHM of the device was 12.9 ps, and the tail was effectively removed.1.4 MHz radio frequency metal-base transistor using single emitter layer
http://dl-live.theiet.org/content/journals/10.1049/el.2011.3235
A report is presented on a study of single emitter layer metal base transistors with a base terminal made of aluminium grids. The latter exhibits low operating voltage associated to the high resistivity of the collector terminal and also shows very low leakage current. With such a single emitter layer, common-emitter current gain, on/off current ratio, and cutoff frequency of, respectively, 239.62, 3.8×10<sup xmlns="http://pub2web.metastore.ingenta.com/ns/">7</sup>, and 1.4 MHz, were obtained.1 fF ESD protection device for gigahertz high-frequency output ESD protection
http://dl-live.theiet.org/content/journals/10.1049/el.2011.1904
A mutual-protection scheme is proposed to achieve an ultra-low capacitance electrostatic discharge (ESD) protection device. The ESD protection device can not only dissipate ESD current, but also can make the vulnerable output transistor have the ESD protection capability. Namely, the output transistor can also protect ICs and help the ESD protection device to share the ESD current. Using this scheme can discharge more ESD current than the summation current of the two individual devices. From the ESD test result, it can achieve the required ESD level by using the ultra-low capacitance ESD protection device (∼1.2 fF).Direct temporal reconstruction of picosecond pulse by cross-correlation in semiconductor device
http://dl-live.theiet.org/content/journals/10.1049/el.2012.1608
Cross-correlation measurements using the two-photon absorption process in a semiconductor is experimentally demonstrated for two pulses of different wavelengths (shifted by ∼200 nm) and durations (20 times ratio). These measurements were found to be highly repeatable and fully suitable for the determination of the temporal intensity profile of picosecond (ps) pulses.Linearisation of MOS resistors using capacitive gate voltage averaging
http://dl-live.theiet.org/content/journals/10.1049/el_20050565
A compact implementation of a scheme to improve linearity of MOS resistors is introduced. It is based on capacitive gate voltage averaging in conjunction with large resistive biasing elements implemented using MOS transistors operating in subthreshold. Experimental results from a test chip in 0.5 µm CMOS technology are shown that verify the proposed technique.50 Ω noise measurements with full receiver calibration without tuner
http://dl-live.theiet.org/content/journals/10.1049/el_19960146
A 50 Ω high frequency noise measurement has been developed. A new approach for calculating the four noise parameters is presented. This method necessitates no isolator and has broad-band capacities. Receiver calibration and <i xmlns="http://pub2web.metastore.ingenta.com/ns/">F</i><sub xmlns="http://pub2web.metastore.ingenta.com/ns/">50</sub> HEMTs measurements are presented.Printable rectifying device using Si-composite
http://dl-live.theiet.org/content/journals/10.1049/el_20082824
The R&D in finding low-cost manufacturing of electronics and electronic components is intense. One research route is aiming at roll-to-roll printing of organic electronics but the typically low mobility in organic semiconductors results in fundamental difficulties to fabricate, e.g., diodes for operation at high frequencies. A novel diode has instead been realised by screen-printing a silicon-powder composite with the intention to utilise the high mobility and the high operation frequency potential of silicon. The current against voltage (<i xmlns="http://pub2web.metastore.ingenta.com/ns/">I</i>-<i xmlns="http://pub2web.metastore.ingenta.com/ns/">V</i>) characteristics of the printed device reveal diode behaviour but so far with a too high ideality factor and resistance to be practically useful. By optimising device geometry, composite, and printing process low-cost printed, high frequency diodes (MHz–some GHz) may be viable.Irradiation induced weak spots in SiO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub> gate oxides of MOS devices observed with C-AFM
http://dl-live.theiet.org/content/journals/10.1049/el_20057289
A nanoscale characterisation of the electrical conduction of irradiated thin SiO<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">2</sub> gate oxides of MOS devices has been performed with a conductive atomic force microscope. The electrical images reveal the existence of weak spots, which have been attributed to the electrical damage induced by irradiation. Although their <i xmlns="http://pub2web.metastore.ingenta.com/ns/">I</i>–<i xmlns="http://pub2web.metastore.ingenta.com/ns/">V</i> characteristics show a leaky behaviour, these locations have not experienced a hard breakdown event.Method for measuring noise parameters of microwave two-port
http://dl-live.theiet.org/content/journals/10.1049/el_19980942
A new tuner-based method for measuring the four noise-parameters of a two-port is proposed. It makes use of a novel measurement ratio that includes noise powers and mismatch factors simultaneously. In contrast to previous works, no restrictions on the noise source, tuner state temperatures and cold temperatures are assumed.