>Magister Scientiae - MSc / Solid-state reactions of bi-metallic systems can be driven or activated by various external
stimuli like pressure, energetic photons, energetic charged particles or heat. For an example,
high pressure torsion can be applied to aluminium-copper (Al-Cu) to drive solid-state reaction
[1.1]. Oh-ishi et al. [1.1] applied a pressure of 6 GPa to Al and Cu half discs. Following this,
x-ray diffraction (XRD) and high-resolution transmission electron microscope (HRTEM) were
used to confirm the formation of different intermetallic phases such as Al2Cu and Al4Cu9.
One of the first reported case where photons were used to drive solid phase diffusion was
reported in 1998 by Ditchfield et al. [1.2]. The study was carried out to study the non-thermal
effects of photons illumination on surface diffusion, an important process in microelectronics
fabrication. Surface diffusion governs several important steps in microelectronics fabrication
including the formation of hemispherical grained silicon used in memory devices [1.2], filling
of channels with metals for devices interconnection purposes among others [1.2]. In this study,
germanium-indium (Ge-In) on silicon was used because the thermal diffusion of this system
was well understood [1.3]. Surface diffusion was measured in ultrahigh vacuum via second
harmonic microscopy when the sample was illuminated with pulsed Nd: YAG laser at a
wavelength of 1064 nm [1.3]. This study showed conclusively that photons could be used to
drive solid-state reactions.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:uwc/oai:etd.uwc.ac.za:11394/8957 |
| Date | January 2021 |
| Creators | Mnguni, Mmangaliso Mpilonde |
| Contributors | Kotsedi, Lebogang |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Format | application/pdf |
| Rights | University of the Western Cape |
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