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Details of Grant 

EPSRC Reference: GR/J90718/01
Principal Investigator: Beaumont, Professor S
Other Investigators:
Long, Professor AR Taylor, Mr M Barker, Professor JR
Wilkinson, Professor C Weaver, Professor JMR Willaimson, Dr J
Thoms, Dr S Stanley, Professor C Sotomayor Torres, Professor C
Asenov, Professor A Davies, Professor JH Williamson, Dr J
McIntyre, Dr D MacIntyre, Dr D
Researcher Co-Investigators:
Project Partners:
Department: Electronics and Electrical Engineering
Organisation: University of Glasgow
Scheme: Standard Research (Pre-FEC)
Starts: 01 April 1994 Ends: 01 April 1996 Value (£): 2,052,295
EPSRC Research Topic Classifications:
Electronic Devices & Subsys. Optoelect. Devices & Circuits
RF & Microwave Technology
EPSRC Industrial Sector Classifications:
Related Grants:
Panel History:  
Summary on Grant Application Form
Generally, to develop techniques for the fabrication of semiconductor nanostructures - structures and devices with critical features less than 0.1 micro-metres in size - and to study their applications in electronics and optoelectronics. The five main topics covered by this rolling grant are:(i) Development of ultrafast electronics for use at 94GHz and 150GHz(ii) Study of quantum and single electron devices at the limits of miniaturisation(iii) Investigation of the emission of light from nanostructures(iv) Enhancement of the resolution of electron beam lithography(v) Growth of layered structures by molecular beam epitaxy(vi) Development of dry-etch processes for nanostructuresProgress:Ultrafast systems. A process for fabricating pseudomorphic HEMTs based entirely on electron beam lithography and dry etching has been developed for use at 94GHz. 0.2-m gate length transistors show state-of-the-art performance at the target frequency. Characterisation of the dry etch process shows that negligible damage is done to the underlying semiconductor material, and that not only the rf noise but also l/f noise is unaffected by the use of dry etching technology. A CFC-free selective etching processes have been developed and is being transferred to industry. A new method of etching indium-containing semiconductors for use at 150GHz has been invented and is undergoing development. Demonstrators for 94GHz and 150GHz transistors are being designed. These devices are also being used by two other EPSRC-sponsored collaborative research projects. Device modelling tools are under development which allow detailed descriptions of device structure and geometry, including recesses of different shapes. Comparison with experimental data is improving our understanding of the interactions between surface charge effects, transport properties and device performance. Monte-Carlo models are being developed for use on parallel supercomputers. These will be used to obtain transport parameters for use in faster, classical drift-diffusion models. Quantum transport and single electronic devices. The thrust of this work is the development of devices which exhibit quantum and single electron effects at liquid helium temperatures, rather than dilution refrigerator temperatures. These would allow special applications in sensing and metrology to be developed, and new investigations of quantum effects at high frequencies to be carried out. By using shallow two-dimensional electron gas layers and electron beam lithography almost at its resolution limit of 10nm we have been able to fabricate devices which show clear quantum effects up to 15K and single electron effects at 4K. Careful modelling of the behaviour of these devices is improving our understanding of the physical principles which govern their operation. Optoelectronics. Here we are studying the emission of light from nanometre-scale structures (quantum wires and quantum dots) fabricated by dry etching and by direct MBE growth. Quantum dots etched in Si/SiGe structures show enhanced luminescence which we attribute to a direct-indirect bandgap transition, and directly-grown structures emit light intensely over a very narrow spectral range. These structures may be useful in future generations of LEDs and lasers. Electron beam lithography. New instrumentation is under construction to make it possible to fabricate 5nm structures. Epitaxial growth. Research has concentrated on the optimised growth of shallow two dimensional electron gas structures and the direct growth of quantum wires on edges.
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