Epioptics Applied to Semiconductor Interfaces

EASI - 6878

Work Area: Alternative Advanced Semiconductor Materials, Devices and Process Steps

Keywords optical characterisation, surface and interface characterisation, semiconductor epitaxial growth, ellipsometry, second harmonic generation

Start Date: 27 May 92 / Duration: 36 months / Status: running

[ participants / contact ]

Abstract New techniques for determining the properties of materials used in information technology devices are being developed. Light is used as both probe and signal ("epioptics"), with extremely high spatial resolution. In contrast to existing techniques, epioptics can be used in situ , while growing crystalline material, in all environments . Applying epioptics to growth processes will provide new insights into the mechanisms involved, thus increasing yield and quality. This work builds on the results of EPIOPTICS (3177).


Emerging process technologies for fabricating sub-micron and nanoscale semiconductor devices and novel multilayer materials all require extremely precise control of growth at surfaces. In situ , non-destructive, real-time monitoring and characterisation of surfaces under growth conditions are needed for further progress in this area, with atomic scale resolution. The main aim of this project is to demonstrate the use of new epioptic techniques for in situ growth monitoring and non-destructive characterisation, for MOVPE, MBE and MOMBE growth in dedicated III-V reactors.

Approach and Methods

EPIOPTIC (3177) showed that new optical techniques have great potential in the area of emerging process technologies: monolayer sensitivity, in situ monitoring of semiconductor growth and complimentary information from different epioptic techniques have been demonstrated on model systems.

In EASI new epioptic techniques for in situ growth monitoring and non-destructive characterisation for MOVPE, MBE and MOMBE III-V growth reactors. In addition, a preliminary assessment of epioptic probes for ultra-clean silicon processing diagnostics will be made. An improved understanding of the origins of the epioptic response from surfaces and interfaces will be sought by studying examples of silicide, III-V and II-VI interfaces in detail, with strong theoretical and conventional surface diagnostics back-up. Six main epioptic techniques will be used: reflectance anisotropy and reflectance difference spectroscopies, spectroscopic ellipsometry, optical second harmonic generation, Raman scattering and photoreflectance. An interdisciplinary team has been assembled to produce a vertically integrated structure: theoretical and experimental physicists, materials scientists, crystal growers and materials analysts.

Progress and Results

Three major results have been obtained so far:


EASI has already demonstrated the feasibility of using optical probes to monitor growth of thin-film IT materials with submonolayer resolutionin situand under all growth conditions. Implementing these new characterisation techniques should result in improved materials and higher yields for the fabrication of future IT semiconductor devices.

Latest Publications

Information Dissemination Activies


Trinity College Dublin - IRL
Physics Department
IRL - Dublin 2


Technische Universität Berlin - D
Universita di Messina - I
INFM-Universita di Roma Tor Vergata - I
University College Cork-NMRC - IRL
University of Liverpool - UK
University of Wales College of Cardiff - UK

Associate Partners

Martin Luther Universität Halle Wittenberg - D
UMIST Manchester - UK


Dr. J.F. McGilp
tel +353/1 7021733
fax +353/1 711759
e-mail: jmcgilp@VAX1.TCD.IE

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EASI - 6878, August 1994

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html version of synopsis by Nick Cook