Dry Etched III-V Semiconductors for Nanoelectronics

Cheung, Rebecca Mei Kwan (1990) Dry Etched III-V Semiconductors for Nanoelectronics. PhD thesis, University of Glasgow.

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The purpose of this work was to try to identify the amount, degree and physical nature of the damage caused on both the surface and sidewalls of reactive ion etched GaAs and AlGaAs nanostructures using a variety of complimentary characterisation techniques, and to develop low damage high resolution dry etch processes for GaAs and AlGaAs. The gases investigated included SiCl4, CH4/H2 and CCl2F2/He. Two new methods of etching GaAs anisotropically by magnetron radio-frequency and electron cyclotron resonance radio-frequency reactive ion etching employing CCl2F2/He, and the use of a novel gas mixture CH4/H2 to reactive ion etch GaAs in the conventional radio-frequency mode were developed. It was found to be important to distinguish between surface and sidewall damage, and both were characterised using electrical, optical as well as analytical techniques. In particular, two novel processes were developed using high resolution fabrication techniques for the construction of sidewall Schottky diodes and electron transparent thin wire specimens to allow the amount of sidewall damage to be estimated and its nature to be realised through diode characteristic measurements and transmission electron microscopy analysis. To investigate the surface damage caused after etching, techniques such as Schottky diode performance, integrated band-gap photoluminescence, Raman scattering and X-ray photoelectron spectroscopy were employed; and for the first time, the usefulness of specular X-ray reflectivity for the identification of surface damage was explored. Sidewall damage was examined using room and low temperature conductivity, and low temperature magnetoconductance of n+ GaAs quantum wires, sidewall Schottky diode characteristics and transmission electron microscopy on thin wire specimens. The dependence of surface and sidewall damage on etch time and etch power was also studied.

Item Type: Thesis (PhD)
Qualification Level: Doctoral
Keywords: Materials science, Electrical engineering, Nanotechnology
Date of Award: 1990
Depositing User: Enlighten Team
Unique ID: glathesis:1990-78076
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 30 Jan 2020 15:41
Last Modified: 30 Jan 2020 15:41
URI: https://theses.gla.ac.uk/id/eprint/78076

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