Low threading dislocation density Ge deposited on Si (100) using RPCVD

Abstract Epitaxial Ge layer growth of low threading dislocation density (TDD) and low surface roughness on Si (1 0 0) surface is investigated using a single wafer reduced pressure chemical vapor deposition (RPCVD) system. Thin seed Ge layer is deposited at 300 °C at first to form two-dimensional Ge surface followed by thick Ge growth at 550 °C. Root mean square of roughness (RMS) of ∼0.45 nm is achieved. As-deposited Ge layers show high TDD of e.g. ∼4 × 10 8  cm −2 for a 4.7 μm thick Ge layer thickness. The TDD is decreasing with increasing Ge thickness. By applying a postannealing process at 800 °C, the TDD is decreased by one order of magnitude. By introducing several cycle of annealing during the Ge growth interrupting the Ge deposition, TDD as low as ∼7 × 10 5  cm −2 is achieved for 4.7 μm Ge thick layer. Surface roughness of the Ge sample with the cyclic annealing process is in the same level as without annealing process (RMS of ∼0.44 nm). The Ge layers are tensile strained as a result of a higher thermal expansion coefficient of Ge compared to Si in the cooling process down to room temperature. Enhanced Si diffusion was observed for annealed Ge samples. Direct band-to-band luminescence of the Ge layer grown on Si is demonstrated.

[1]  Gang Wang,et al.  Fabrication of high quality Ge virtual substrates by selective epitaxial growth in shallow trench isolated Si (001) trenches , 2010 .

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

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

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

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

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

[7]  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 .

[8]  Thomas A. Langdo,et al.  Controlling threading dislocation densities in Ge on Si using graded SiGe layers and chemical-mechanical polishing , 1998 .

[9]  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 .

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

[11]  Krishna C. Saraswat,et al.  Effect of isochronal hydrogen annealing on surface roughness and threading dislocation density of epitaxial Ge films grown on Si , 2010 .

[12]  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 .