Low threading dislocation Ge on Si by combining deposition and etching

Abstract Blanket and selective Ge growth on Si is investigated using reduced pressure chemical vapor deposition. To reduce the threading dislocation density (TDD) at low thickness, Ge deposition with cyclic annealing followed by HCl etching is performed. In the case of blanket Ge deposition, a TDD of 1.3 × 10 6  cm − 2 is obtained, when the Ge layer is etched back from 4.5 μm thickness to 1.8 μm. The TDD is not increased relative to the situation before etching. The root mean square of roughness of the 1.8 μm thick Ge is about 0.46 nm, which is of the same level as before HCl etching. Further etching shows increased surface roughness caused by non-uniform strain distribution near the interface due to misfit dislocations and threading dislocations. The TDD also becomes higher because the etchfront of Ge reaches areas with high dislocation density near the interface. In the case of selective Ge growth, a slightly lower TDD is observed in smaller windows caused by a weak pattern size dependence on Ge thickness. A significant decrease of TDD of selectively grown Ge is also observed by increasing the Ge thickness. An about 10 times lower TDD at the same Ge thickness is demonstrated by applying a combination of deposition and etching processes during selective Ge growth.

[1]  Ka Wai Wong,et al.  Field-emission characteristics of SiC nanowires prepared by chemical-vapor deposition , 1999 .

[2]  Y. Bogumilowicz,et al.  Reduced pressure-chemical vapor deposition of intrinsic and doped Ge layers on Si(0 0 1) for microelectronics and optoelectronics purposes , 2005 .

[3]  G. Masini,et al.  Ge/Si (001) Photodetector for Near Infrared Light , 1997 .

[4]  Cheng Li,et al.  The influence of low-temperature Ge seed layer on growth of high-quality Ge epilayer on Si(100) by ultrahigh vacuum chemical vapor deposition , 2008 .

[5]  Elia Palange,et al.  Metal–semiconductor–metal near-infrared light detector based on epitaxial Ge/Si , 1998 .

[6]  Yuji Yamamoto,et al.  Low threading dislocation density Ge deposited on Si (100) using RPCVD , 2011 .

[7]  Thomas A. Langdo,et al.  High-quality germanium photodiodes integrated on silicon substrates using optimized relaxed graded buffers , 1998 .

[8]  Gang Wang,et al.  A model of threading dislocation density in strain-relaxed Ge and GaAs epitaxial films on Si (100) , 2009 .

[9]  Eaglesham,et al.  Dislocation-free Stranski-Krastanow growth of Ge on Si(100). , 1990, Physical review letters.

[10]  L. Clavelier,et al.  Epitaxial growth of Ge thick layers on nominal and 6° off Si(0 0 1); Ge surface passivation by Si , 2009 .

[11]  Laurent Vivien,et al.  Reduced pressure–chemical vapor deposition of Ge thick layers on Si(001) for 1.3–1.55-μm photodetection , 2004 .

[12]  Yves Campidelli,et al.  Chemical vapour etching of Si, SiGe and Ge with HCl; applications to the formation of thin relaxed SiGe buffers and to the revelation of threading dislocations , 2005 .

[13]  A. Satta,et al.  Benefits and side effects of high temperature anneal used to reduce threading dislocation defects in epitaxial Ge layers on Si substrates , 2008 .

[14]  Kazumi Wada,et al.  High-quality Ge epilayers on Si with low threading-dislocation densities , 1999 .

[15]  Jacobson,et al.  Growth morphology and the equilibrium shape: The role of "surfactants" in Ge/Si island formation. , 1993, Physical review letters.

[16]  James S. Harris,et al.  Low surface roughness and threading dislocation density Ge growth on Si (0 0 1) , 2008 .

[17]  R. Kurps,et al.  B atomic layer doping of Ge , 2010 .