HCl Selective Etching of Si1-xGex versus Si for Silicon On Nothing and Multi Gate Devices

Autor:	V Destefanis, Jean-Michel Hartmann, Florian Hüe, Daniel Bensahel
Rok vydání:	2008
Předmět:	Materials science Silicon chemistry Etching (microfabrication) business.industry Inorganic chemistry Optoelectronics chemistry.chemical_element business
Zdroj:	ECS Transactions. 16:427-438
ISSN:	1938-6737 1938-5862
DOI:	10.1149/1.2986800
Popis:	We have studied the low temperature (~ 650oC), high HCl partial pressure (180 Torr) selective etch of SiGe versus Si inside a RP-CVD reactor. The surface roughness strongly increases while vertically etching fullsheet Si1-xGex layers. We have also laterally etched (Si / SiGe) multilayers patterned along the directions. The best selectivities and the highest SiGe etch rates have been obtained for the highest Ge content studied, i.e. 40%. facets have been revealed at the end of tunnels. A strong increase (x 18) of the lateral HCl etch rates has been evidenced when increasing the Si0.6Ge0.4 layer thickness from 5 up to 20 nm. Very good SiGe versus Si selectivities have been obtained with slightly higher etch rates than on bulk Si when HCl etching (Si / SiGe) multilayers grown on Si0.8Ge0.2 virtual substrates. Finally, a strong HCl etch in-plane anisotropy has always been evidenced. oriented pattern corners are indeed far more etched than oriented edges.
Databáze:	OpenAIRE
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