MMU Home | Prospectus | About MMU | A-Z Index | Contacts 
 


mmuch more
 
Search:
bullet
Browse
Collection All
bullet
bullet
bullet
bullet
bullet
Listed communities
bullet
bullet
bullet
bullet

espace at MMU > Faculties > Faculty of Science and Engineering > Centre for Materials Science Research: Surface Coating and Characterisation Research Group  > Dose dependence of formation of nanoscale cavities in helium-implanted 4H–SiC

Please use this identifier to cite or link to this item: http://hdl.handle.net/2173/110758
    Del.icio.us     LinkedIn     Citeulike     Connotea     Facebook     Stumble it!

SFX Query

Title: Dose dependence of formation of nanoscale cavities in helium-implanted 4H–SiC
Authors: Zhang, C. H.
Donnelly, Steve E.
Vishnyakov, Vladimir
Evans, J. H.
Citation: Journal of applied physics, 2003, vol. 94, no. 9, pp. 6017-6022.
Publisher: American Institute of Physics
Issue Date: Nov-2003
URI: http://hdl.handle.net/2173/110758
DOI: 10.1063/1.1611630
Additional Links: http://link.aip.org/link/JAPIAU/v94/i9/p6017/s1&Agg=doi
Abstract: A cross-sectional transmission electron microscope investigation of dose dependence and annealing behavior of microstructures in helium-implanted silicon carbide is presented. Specimens of silicon carbide (4H–SiC) were mainly implanted with 30-keV-He ions at intermediate temperatures of 500 and 873 K to doses ranging from 5×1015 to 2×1017 cm−2, and subsequently annealed at temperatures up to 1173 K. For comparison other specimens were implanted at 293 K up to 5×1015 cm−2 and subsequently annealed. Three dose regimes of microstructural evolution were found, each of them exhibiting quite different annealing behavior. No cavities were found at the low dose range below 3.5×1016 cm−2. At intermediate doses of (3.5–5)×1016 cm−2, a low density of planar clusters of bubbles located in the basal plane was found in a well defined region around the damage peak on annealing above 973 K. After implantation to the high dose of 1017 cm−2, a high density of bubbles in alignment in the basal plane was formed, and remained stable during the subsequent annealing at temperatures up to 1173 K. The difference in annealing behavior suggests that helium is trapped with different energies for the three dose regimes. There appears to be a threshold dose for the formation of the bubble clusters of approximately 5×1015 cm−2 for implantation at room temperature. This increases to a value between 2×1016 and 5×1016 cm−2 for implantation at 500 and 873 K, respectively. Such a temperature dependence is consistent with that of effective damage production, indicating a certain level of damage is necessary for the formation of bubble clusters. The formation of planar clusters of bubbles at the intermediate doses is ascribed to an Ostwald ripening (OR) process through the dissociation of the simple He/vacancy clusters and metastable bubbles and the formation of planar cavities of helium on annealing above 973 K.
Type: Article
Language: en
Description: Full-text of this article is not available in this e-prints service. This article was originally published [following peer-review] in Journal of Applied Physics, published by and copyright American Institute of Physics.
Keywords: Silicon compounds
Wide band gap semiconductors
Helium
Semiconductor doping
Ion implantation
Transmission electron microscopy
ISSN: 0021-8979
Appears in Collections: Centre for Materials Science Research: Surface Coating and Characterisation Research Group

Files in This Item:

There are no files associated with this item.



All Items in e-space are protected by copyright, with all rights reserved, unless otherwise indicated.

 

OR Logo Powered by Open Repository | Cookies
Valid XHTML 1.0!