Applied Surface Science, Vol.254, No.19, 6037-6039, 2008
Selective vapor phase etching of SiGe by HCl in a RPCVD reactor
Chemical vapor phase etching of epitaxial SiGe by HCl was investigated using a single wafer reduced pressure CVD (RPCVD) system. For the sample preparation, patterning and dry etching were performed on the Si substrate with SiGe buried layers to open the sidewalls of the buried SiGe layers. The etchrate of the lateral direction was measured. The etchrate of SiGe is increasing with increasing SiGe thickness saturating at SiGe thicknesses higher than similar to 25 nm. This result could be caused by diffusion effects of molecules in the narrow trenches during the etching. At the same SiGe thickness, the etchrate of SiGe is increasing with increasing etching temperature. B doping does not affect the etchrate of SiGe. P doping is increasing and C doping is decreasing the etchrate. Facet formation of the etchfront of Si and SiGe depends on initial surface orientation. These results enable improved process controllability of the etching process using doped layers for different applications. (c) 2008 Elsevier B.V. All rights reserved.