Structural properties of hydrogenated amorphous silicon (A-SI:H) thin film grown via radio frequency plasma enhanced chemical vapor deposition (RF PECVD)

An investigation of the structural properties of hydrogenated amorphous silicon (a-Si:H) thin films prepared by plasma enhanced chemical vapour deposition of silane (SiH4) was done using a combination of atomic force microscopy (AFM), photoluminescence, infrared and UV spectroscopy. Films were prepa...

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Main Author:	Anthony Hasbi, Hasbullah
Format:	Thesis
Language:	English
Published:	2005
Subjects:	QC Physics
Online Access:	http://eprints.utm.my/id/eprint/5093/1/HasbullahAnthonyHasbiMFS2005.pdf
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spelling	my-utm-ep.50932018-02-28T06:52:56Z Structural properties of hydrogenated amorphous silicon (A-SI:H) thin film grown via radio frequency plasma enhanced chemical vapor deposition (RF PECVD) 2005-06 Anthony Hasbi, Hasbullah QC Physics An investigation of the structural properties of hydrogenated amorphous silicon (a-Si:H) thin films prepared by plasma enhanced chemical vapour deposition of silane (SiH4) was done using a combination of atomic force microscopy (AFM), photoluminescence, infrared and UV spectroscopy. Films were prepared with rf power ranging from 100-250 W. For every rf power employed, substrate temperature were varied from room temperature to 300Â°C. The deposition rate was found to be slightly increasing with an increase of rf power while decreasing as the substrate temperature increases. The AFM images can be classified into three groups: most smooth (rms: 1.2nm), intermediate rms (2.4-3.6 nm) and highest roughness (rms: 4.9 nm). The transition to rougher films at higher substrate temperature is attributed to a change in the deposition process. The IR vibrational spectra obtained from FTIR spectroscopy display modes which can be characterized as predominantly hydrogen motions. On the basis of these identifications, it is found that samples produced on high-temperature have SiH, SiH2 and (SiH2)n groups with very little SiH3. In contrast, the ir spectra of samples produced on room-temperature are dominated by vibrational modes of SiH3 and (SiH2)n. At low rf power, the spectrum is dominated by a strong absorption bands at 2000 cm-1 associated with SiH stretching bond and also 630 cm-1 associated with SiH bending. At high rf power, an additional absorption band at around 2090 cm-1 which corresponds to (SiH2)n stretching mode and SiH2 stretching mode becomes more pronounced. The optical energy gap obtained from UV spectroscopy decreases with increasing of rf power and substrate temperature. This decrement is due to the drop of hydrogen content. At low substrate temperature, photoluminescence spectrum of a-Si consists of a relatively broad band with its main peak around 1.4 eV. The spectrum shifts to lower energies (around 1.37 eV) and its intensity decreases with increasing temperature. It is suggested that this is due to an activated non-radiative recombination (relaxation) process where exciton are captured by deep traps and this become more probable as temperature increases. 2005-06 Thesis http://eprints.utm.my/id/eprint/5093/ http://eprints.utm.my/id/eprint/5093/1/HasbullahAnthonyHasbiMFS2005.pdf application/pdf en public masters Universiti Teknologi Malaysia, Faculty of Science Faculty of Science
institution	Universiti Teknologi Malaysia
collection	UTM Institutional Repository
language	English
topic	QC Physics
spellingShingle	QC Physics Anthony Hasbi, Hasbullah Structural properties of hydrogenated amorphous silicon (A-SI:H) thin film grown via radio frequency plasma enhanced chemical vapor deposition (RF PECVD)
description	An investigation of the structural properties of hydrogenated amorphous silicon (a-Si:H) thin films prepared by plasma enhanced chemical vapour deposition of silane (SiH4) was done using a combination of atomic force microscopy (AFM), photoluminescence, infrared and UV spectroscopy. Films were prepared with rf power ranging from 100-250 W. For every rf power employed, substrate temperature were varied from room temperature to 300Â°C. The deposition rate was found to be slightly increasing with an increase of rf power while decreasing as the substrate temperature increases. The AFM images can be classified into three groups: most smooth (rms: 1.2nm), intermediate rms (2.4-3.6 nm) and highest roughness (rms: 4.9 nm). The transition to rougher films at higher substrate temperature is attributed to a change in the deposition process. The IR vibrational spectra obtained from FTIR spectroscopy display modes which can be characterized as predominantly hydrogen motions. On the basis of these identifications, it is found that samples produced on high-temperature have SiH, SiH2 and (SiH2)n groups with very little SiH3. In contrast, the ir spectra of samples produced on room-temperature are dominated by vibrational modes of SiH3 and (SiH2)n. At low rf power, the spectrum is dominated by a strong absorption bands at 2000 cm-1 associated with SiH stretching bond and also 630 cm-1 associated with SiH bending. At high rf power, an additional absorption band at around 2090 cm-1 which corresponds to (SiH2)n stretching mode and SiH2 stretching mode becomes more pronounced. The optical energy gap obtained from UV spectroscopy decreases with increasing of rf power and substrate temperature. This decrement is due to the drop of hydrogen content. At low substrate temperature, photoluminescence spectrum of a-Si consists of a relatively broad band with its main peak around 1.4 eV. The spectrum shifts to lower energies (around 1.37 eV) and its intensity decreases with increasing temperature. It is suggested that this is due to an activated non-radiative recombination (relaxation) process where exciton are captured by deep traps and this become more probable as temperature increases.
format	Thesis
qualification_level	Master's degree
author	Anthony Hasbi, Hasbullah
author_facet	Anthony Hasbi, Hasbullah
author_sort	Anthony Hasbi, Hasbullah
title	Structural properties of hydrogenated amorphous silicon (A-SI:H) thin film grown via radio frequency plasma enhanced chemical vapor deposition (RF PECVD)
title_short	Structural properties of hydrogenated amorphous silicon (A-SI:H) thin film grown via radio frequency plasma enhanced chemical vapor deposition (RF PECVD)
title_full	Structural properties of hydrogenated amorphous silicon (A-SI:H) thin film grown via radio frequency plasma enhanced chemical vapor deposition (RF PECVD)
title_fullStr	Structural properties of hydrogenated amorphous silicon (A-SI:H) thin film grown via radio frequency plasma enhanced chemical vapor deposition (RF PECVD)
title_full_unstemmed	Structural properties of hydrogenated amorphous silicon (A-SI:H) thin film grown via radio frequency plasma enhanced chemical vapor deposition (RF PECVD)
title_sort	structural properties of hydrogenated amorphous silicon (a-si:h) thin film grown via radio frequency plasma enhanced chemical vapor deposition (rf pecvd)
granting_institution	Universiti Teknologi Malaysia, Faculty of Science
granting_department	Faculty of Science
publishDate	2005
url	http://eprints.utm.my/id/eprint/5093/1/HasbullahAnthonyHasbiMFS2005.pdf
_version_	1747814561984020480

Structural properties of hydrogenated amorphous silicon (A-SI:H) thin film grown via radio frequency plasma enhanced chemical vapor deposition (RF PECVD)

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