Qinetiq Limited

The Secretary of State for Defence in Her Britannic Majesty's Government

The Secretary of State for Defence

The Secretary of State for Defence in Her Britannic Majesty's Government of the United Kingdom of Great Britain and Northern Ireland

The Secretary of State for Business Innovation and Skills in Her Britannic Majesty's Government of the United Kingdom of Great Britain and Nothern Ireland

Timothy Ashley

Charles Thomas Elliott

Neil Thomson Gordon

Timothy Jonathan Phillips

Ralph S Hall

Graham J Pryce

Ian Charles Sage

Timothy Ingram Cox

Anthony M White

Kevin Michael Brunson

David J Combes

John Henry Jefferson

Anthony B Dean

Geoffrey Richard Nash

Stanley D Smith

John Graham Crowder

Norman J Geddes

Volker P Manheim

Russell A Noble

Philip D Buckle

Ralph Stephenson Hall

David George Gleaves

Charles Thomas Elliot

Ian Charles Carmichael

Colin R Whitehouse

Ralph Stephen Hall

Anthony Brian Dean

A semiconductor device comprising a plurality of regions of semiconductor material forming a junction at an interface there-between, the junction including a depletion region having a width which varies spatially in at least one direction along the depletion region. Without limitation, the spatial variation in depletion region width is provided by ionised dopants having a concentration which varies spatially along said at least one direction. Alternatively, or in addition, the spatial variation in depletion region width is achieved by varying the thickness of the region(s) of semiconductor spatially along said at least one direction, for example by creating a plurality of cells within said region(s) devoid of said semiconductor material. A method of fabricating a semiconductor device comprising the step of varying the width of the depletion region spatially there-within in at least one direction along the depletion region.

Semiconductor device and fabrication method

In a transistor in which the majority carriers are holes, at least one narrow bandgap region or layer is doped p-type or contains an excess of holes and is subject to compressive mechanical strain, whereby hole mobility may be significantly increased. In a p-channel quantum well FET, the quantum well InSb well p-type layer(modulation or directly doped) lies between InAlSb layerswhere x is of a value sufficient to induce strain in layerto an extent that light and heavy holes are separated by much more than kT. Transistors falling within the invention, including bipolar pnp devices, may be used with their more conventional electron majority carriers counterparts in complementary logic circuitry.

Strained quantum-well semiconductor devices

A communications system incorporates a transmitter a receiver. The transmitter includes an infrared light emitting diode (LED). The LED output is positive or negative luminescence, i.e. above or below an equilibrium background intensity level respectively, according to the polarity of its bias signal. The receiver contains a lens to focus light from the LED onto a diode detector, from which signals pass to an amplifier, decoder and printer. Output signals from the LED have an average intensity equal to the equilibrium background intensity level and a frequency greater than 100 Hz or byte rate greater than 100 bytes/sec. They are not discernible by conventional thermal infrared imagers with frame rates of 50 Hz or less because integration in such an imager renders them indistinguishable from background.

Communications system

A molecular single electron transistor (MSET) detector device () is described that comprises at least one organic molecule () connecting a drain electrode () and a source electrode (). In use, said at least one organic molecule () provides a quantum confinement region. At least one analyte receptor site () is provided in the vicinity of said at least one organic molecule () that bind molecules of interest (analytes). A fluid analyser () is also described that includes the MSET detector, a pre-concentrator () and a fluid gating structure (). The fluid gating structure () is arranged to selectively route fluid from the pre-concentrator () to either one of the detector () and an exhaust port (). The pre-concentrator (), fluid gating structure () and detector () are each formed as substantially planar layers and arranged in a stack or cube.

Molecular single electron transistor (MSET) detector device

An infrared light emitting diode arrangement comprising an infrared light emitting diode which emits positive luminescence when forward biased and emits negative luminescence when reverse biased. The diode is driven by an alternating forward and reverse bias input so that the difference in output power between the positive luminescence and the negative luminescence of the light emitting diode is stabilised with respect to temperature. The infrared light emitting diode arrangement has particular application as a source in gas sensors and reduces or eliminates temperature control requirements for infrared light emitting diode sources.

Infrared light emitting diodes

The invention provides a Hall effect magnetic field sensor ( ) including carrier excluding or extracting means ( ) for reducing an intrinsic contribution to carrier concentration in the active region ( ) to provide for the sensor to be operative in an extrinsic saturated regime. This provides an advantage that magnetic field measurement sensitivity of the sensor ( ) can be made substantially insensitive to sensor temperature thereby improving measurement accuracy.

Magnetic field sensor including carrier excluding for reducing an instrinsic contribution to carrier concentration in the active region

A field effect transistor (FET) is of the type which employs base biasing to depress the intrinsic contribution to conduction and reduce leakage current. It incorporates four successive layers ( to ): a p InSb base layer ( ), a InAlSb barrier layer ( ), a &pgr; intrinsic layer ( ) and an insulating SiO layer ( ); p source and drain regions ( ) are implanted in the intrinsic layer ( ). The FET is an enhancement mode MISFET ( ) in which biasing establishes the FET channel in the intrinsic layer ( ). The insulating layer ( ) has a substantially flat surface supporting a gate contact ( ). This avoids or reduces departures from channel straightness caused by intrusion of a gate groove, and enables a high value of current gain cut-off frequency to be obtained. In FETs with layers that are not flat, departures from channel straightness should not be more than 50 nm in extent, preferably less than 5 nm.

High frequency field effect transistor with carrier extraction to reduce intrinsic conduction

A semiconductor device wherein the layer of highly doped p-type material typically found in devices of the prior art is replaced with a layer of doped n-type material, having a doping concentration of between 1&times;10 cm and less than 1&times;10 cm , and a thin layer of doped p type material thus facilitating low resistance contact, transparency to radiation produced by the device and confinement with low loss of radiation produced by laser devices.

Low resistance contact semiconductor diode

A thermal imaging system (,) which is accoupled and by scanning recreates a thermal image by superimposing measured variations in infrared emission from a scene (,) onto a reference level supplied by a light emitting diode (,). The diode (,) is both a positive and negative luminescent emitter. Emitted flux is current controlled to be equivalent to black body radiation at a range of temperatures which may be colder or hotter than ambient. A signal generated with the system (,) switches between scene and diode observation is a measure of the difference between the mean scene temperature and the diode effective temperature. In response to this digital, control means adjust the bias current through the diode (,) in order to reduce the temperature difference. The reference temperature converges towards the mean scene temperature as this process is repeated. Absolute temperature is thus restored and some image defects removed.

Thermal imaging system

Thermal sensing system having a fast response calibration device

Infrared optical system

Dynamic infrared scene projector

Semiconductor device with low thermally generated leakage current

A photodetector of semiconductor material includes a photosensitive region adjacent to a minority carrier extraction region arranged when biased to depress the photosensitive region minority carrier concentraction, and means for inhibiting injection of minority carriers to the photosensitive region. Depression of the minority carrier concentration produces low noise and high responsivity properties as obtained by cooling, but without the need for cooling equipment. The minority carrier extraction region may be a pn homo- or heterojunction. Minority carrier injection may be inhibited by a homo- or hetero-structure excluding contact to the photosensitive region, or alternatively by providing the photosensitive region with at least one subsidiary pn junction biasable to inhibit minority carrier flow. The photosensitive region may have an array of extraction regions spaed by less than a minority carrier diffusion length. The extraction regions may have separate outputs to provide respective pixels in a display.

Photodetector semiconductor which does not require extensive cooling

Growing community of inventors

Malvern, United Kingdom

Timothy Ashley