Epioptics Applied to Semiconductor Interfaces
Description
- Project Title:
- Epioptics Applied to Semiconductor Interfaces
- Acronym:
- EASI
- Number:
- 6878
- Work Area:
- Alternative Advanced Semiconductor Materials, Devices and Process Steps
- Coordinator:
- Trinity College Dublin
Physics Department
IRL - Dublin 2
- Coordinator Country:
- IRL
- Partners
- 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
- Contact Point:
- Dr. J.F. McGilp
- Telephone:
- +353/1 7021733
- Fax:
- +353/1 711759
- E-Mail:
- jmcgilp@VAX1.TCD.IE
- Keywords:
- optical characterisation, surface and interface characterisation, semiconductor epitaxial growth, ellipsometry, second harmonic generation
- Start Date:
- 27 May 92
- Duration:
- 36 months
- Status:
- running
- 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).
AIMS
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:
- growth of III-V epitaxial layers in an atmospheric pressure MOVPE reactor has been monitored in real time, with sub-monolayer resolution, using reflection anisotropy spectroscopy (RAS) - the number of single atomic layers grown is simply determined by counting the number of oscillations in the RAS signal
- growth of II-VI epitaxial layers has been monitored, in situ and in real time, using Raman spectroscopy, with sub-monolayer resolution - evidence of chemical reactivity at the II-VI/III-V interface has been obtained
- a combination of linear optical theory and experiment has resolved a long-standing controversy on the nature of the dimer structure on the surface of Si(001).
POTENTIAL
EASI has already demonstrated the feasibility of using optical probes to monitor growth of thin-film IT materials with submonolayer resolution in situ and 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
- Shkrebtii A I and Del Sole R Microscopic calculation of the optical properties of Si(100)-2xl: Symmetric versus Asymmetric Dimers Phys. rev. Lett. 70, 2645 (1993)
- Power J R and McGilp J F A I Resonance in the optical second harmonic response from the Si(111)-Sb interface Surf. Sci. 287/8, 708 (1993)
- Rossow U, Frotscher U, Richter W and Zahn D R T In situ optical characterisation with monolayer sensitivity: the As-terminated Si(111) surface Surf. Sci. 287/8, 718 (1993)
- Shen T H and Matthai C C Calculation of the optical properties of As molecules on Si substrates Surf. Sci. 287/8, 672 (1993
- Piparo E and Girlanda R Linear and non-linear optical properties of surfaces and spatially non-local potentials Surf. Sci. 287/8, 699 (1993)
INFORMATION DISSEMINATION ACTIVITIES
- Third Epioptic Workshop, Dublin September 1993: Optical characterisation of semiconductor surfaces and interfaces.
- Research papers presented at the following international conferences:
E-MRS Spring Meeting, Strasbourg, June 1992
IVC-12/ICSS-8, The Hague, October 1992
MRS Fall Meeting, Boston, November 1992
ICSE-93, Paris, January 1993
Royal Society Discussion Meeting, London, March 1993
E-MRS Spring Meeting, Strasbourg, May 1993.
- Video of in situ growth monitoring, using light, in a molecular beam epitaxy system.
Sven Müßig, last update 07-nov-1995. Your feedback is welcome.