Semiconductor Research at the Materials-Device Interface

Lead Research Organisation: University of Manchester
Department Name: Electrical and Electronic Engineering

Abstract

This proposal concerns research into electronic materials, and the development of experimental methods designed to improve our measurement capability on the nm scale. Semiconductor materials and devices are central to manufacturing, healthcare, security, administration and leisure. This pivotal position in our lives has developed gradually but is due in the main to dramatic changes that have occurred quite recently. Over the last decade semiconductor technology has begun to experience a revolution in terms of functionality based on decreased size and increased complexity, and this trend will define the future for the entire manufacturing sector. This presents immense challenges to both researchers and to manufacturers of semiconductors because the key issues are no longer the properties of bulk materials or even two-dimensional structures but the properties of small heterogeneous clusters of atoms (semiconductor, dielectric and metal) that constitute today's functional device. To put this into context, the next generation silicon NMOS transistor (45nm node) is only half the size of an influenza virus and for most applications will work in conjunction with tens of millions of similar devices. For research, development and control in manufacture the electronic and physical properties of small atomic clusters need to be probed and interactions with structures in close proximity understood.As materials and device sub-structures become more complex the experimental task of obtaining precise information becomes ever more challenging. In particular the atomic organisation and local chemistry can have a profound effect on electronic behaviour and there is a growing need to develop measurement methods which can both image structures and link shape with local spectroscopic information. In our work we are pushing forward such methods by combining x-ray spectroscopy with scanning probe imaging, using both national and international synchrotron radiation sources. In a complementary approach, we are extending electron energy loss techniques in scanning transmission electron microscopy to link chemical and structural information. Optical spectroscopy is an invaluable tool for characterising condensed matter and we are developing free electron laser pumped Raman spectroscopy in order to directly probe electron states in ultra small semiconductors.Almost all emerging device technologies are limited by these materials issues and much of our work is guided by measuring and understanding these. For example, ultra high speed, low noise detectors and amplifiers are desperately needed by radio-astronomers for the next generation of telescopes. Such devices demand near perfect material and interface properties and form part of our programme. Similarly future THz emitters are hugely challenging in terms of materials physics. One of the key developments in electronic materials in the last decade is the ability to synthesise quantum dots which give three dimensional control over quantum size effects and hold the promise of highly tuneable materials. Measuring the collective electrical properties has proved a major task and the information required to build many devices is missing. We are extending and adapting point defect measurement methods to close this gap. The increasing complexity of materials raises many issues for the device and circuit designer. An important feature of our proposed work is that we aim to include device design concepts at the materials level, and will use this work to guide our experimental programme.

Publications

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Coutinho J (2012) Electronic and dynamical properties of the silicon trivacancy in Physical Review B

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Markevich V (2011) Tin-vacancy complex in germanium in Journal of Applied Physics

 
Description This work led to the discovery of a new nano-composite material in which gold nanoparticles were distributed over the internal nano-surfaces of nano-porous alumina (sapphire).

We discovered that the resulting sensitivity for x-radiation sensing was enhanced by more than an order of magnitude compared with the response of alumina used in an optically stimulated luminescence mode . The mechanism for this improvement was identified as the strong interaction between x-ray photons and metal nano-particles and the subsequent transfer of energy from the nano-particle to the alumina.
Exploitation Route The development of new nano-composite materials which exploit high atomic number nano-particles is generically useful for new radiation detectors. In particular we hope that a new class of sensitive detector array technology, exploiting such materials, will emerge and will play a key role in enhancing the delivery proton and x-ray therapy.

The work has been taken up by NHS groups specialising in radiotherapy
Sectors Energy,Healthcare

 
Description Semiconductor Research at the Materials Device Interface
Amount € 800,579 (EUR)
Funding ID EP/E027261/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Academic/University
Country United Kingdom
Start 05/2007 
End 10/2012
 
Description CERN 
Organisation European Organization for Nuclear Research (CERN)
Department ATLAS Collaboration
Country Switzerland 
Sector Private 
PI Contribution My Group has provided experimental practice and model calculations for detector improvement based on high atomic number nano-particle integration.
Collaborator Contribution The ATLAS detector group have provided materials for processing in Manchester and fully developed technology for benchmarking.
Impact This work is still in the development stage but tests are being planned on a prototype technology.
Start Year 2011
 
Description Christie X-Ray matter interactions with solids for dosimetry 
Organisation The Christie NHS Foundation Trust
Department Oncology Christie NHS Foundation Trust
Country United Kingdom 
Sector Public 
PI Contribution My group has had full access to clinical x-ray sources at the Christie NHS therapy centre, for testing new solid state detector systems. We have injected new ideas for increasing sensitivity and for in vivo sensing. This work is on going and a the development of a new research project between our two organisations is under-way.
Collaborator Contribution The Christie have allocated manpower and facilities to help push forward the testng of the new materials synthesised and devices fabricated in my group.
Impact This is multidisciplinary, covering materials physics, electronics, medical technology. The work was folded into a Quantum Technology Hub bid on "Quantum Sensing for Healthcare Snsing for Healthcare which was selected for final interview but was not funded. The output is to date is subject to confidentiality agreement but the key science outcomes will be presented to the 2015 international CHAOS meeting (Paris, May 2015).
Start Year 2009
 
Description NIMS Skuba 
Organisation National Institute for Materials Sciences
Country Japan 
Sector Academic/University 
PI Contribution We have hosted (for a two year period) a visiting scientist supported by Riken and NIMS who has made use of the specialist facilities within the Photon Science Institute. This has lead to around a dozen joint publications.
Collaborator Contribution NIMS have built and shipped specialist AFM systems for use on synchrotron and laser beam lines. These systems remain in use and form part of our development plans.
Impact The outcomes have principally been the establishment of new experimental tools for semiconductor characterisation using x-ray photons.
 
Description TU Delft 
Organisation Delft University of Technology (TU Delft)
Country Netherlands 
Sector Academic/University 
PI Contribution We have developed a process technology which has demonstrated large improvement in dosimetry sensitivity
Collaborator Contribution Background knowledge and measurement skill transfer.
Impact We are planning a joint research activity/funding bid.
Start Year 2008
 
Description Ttyndall 
Organisation University College Cork
Department Tyndall National Institute
Country Ireland 
Sector Academic/University 
PI Contribution We have advised on electrical spectroscopy using transient capacitance, on defect structure of insulating solids and on surface state screening and anti screening in junction structures.Manchester has hosted regular visits from Tyndall staff.
Collaborator Contribution Tyndall have helped with impedance spectroscopy and with parametrisation of our model calculations and have hosted many reciprocal visits from Manchester staff.
Impact Our involvement with Tyndall has led to our participation in several international meetings.
Start Year 2006