Selective Epitaxial Growth of Si and Si_1-xGe_x Films by Ultrahigh-Vacuum Chemical Vapor Deposition Using Si₂H₆ and GeH₄

Abstract

Aiming at the precise profile control of Si1-x Ge x , selective epitaxial growth (SEG) conditions and Si1-x Ge x growth were investigated by ultrahigh-vacuum chemical vapor deposition (UHV-CVD) using Si2H6 and GeH4. As long as the total amount of Si2H6 did not exceed the critical amount, Si- and Si1-x Ge x -SEG were both achieved independent of source gas flow rate and substrate temperature. The Ge fraction x of Si1-x Ge x could be decided by the flow rate ratio between Si2H6 and GeH4, independent of substrate temperature. Fast gas flow switching realized the formation of a Si(120 Å)/Si1-x Ge x (69 Å) strained layer superlattice at 587°C.

Phosphorus doping of Si and Si1−xGex grown by ultrahigh vacuum chemical vapor deposition using Si2H6 and GeH4

“…Although the quality of the epilayers is good enough for device applications, it shows a very low Si growth rate and some limits in selective epitaxial growth ͑SEG͒ application. 10 Recently, a novel UHVCVD process with a water-cooled cold wall reactor using disilane (Si 2 H 6 ) and germane (GeH 4 ) source gases has been proposed to get high quality Si/Si 1Ϫx Ge x epilayers and successful SEG capability. [11][12][13][14] Therefore, this technique was used to grow Si/Si 1Ϫx Ge x epilayers in this study.…”

Boron incorporation in Si1−xGex films grown by ultrahigh vacuum chemical vapor deposition using Si2H6 and GeH4

“…The variation tendency of the Ge fraction with GeH 4 flow is similar to those of other reports. 6,11 The dependence of the growth rate on the germane flow rate is also shown in Fig. 2.…”

“…Boron incorporation in Si 1؊x Ge x films grown by ultrahigh vacuum chemical vapor deposition using Si 2 H 6 and GeH 4 L. P. Chen and C. T. Chou 6 diluted in hydrogen is used as the p-type dopant gas in Si 1Ϫx Ge x grown by ultrahigh vacuum chemical vapor deposition ͑UHVCVD͒ using Si 2 H 6 and GeH 4 . The boron concentration is evaluated by secondary ion mass spectrometry ͑SIMS͒.…”

“…However, the growth rate of Si is very low and shows some limits in selective epitaxial growth ͑SEG͒ application. 6 Recently, a novel UHVCVD process with a cold wall reactor using Si 2 H 6 and GeH 4 gases has been developed to get high quality Si 1Ϫx Ge x films and SEG capability. 7,8 In this study, we used similar UHVCVD process to grow Si and Si 1Ϫx Ge x films.…”

“…Furthermore, we also check the boron concentration of the SiGe films grown at different growth temperatures ͑525-575°C͒. The Ge fraction 6 and boron concentration were kept nearly constant in this study. These results suggest that there is not a kinetic barrier for boron incorporation in SiGe epitaxy and a thermodynamic equilibrium is obtained between boron in gas phase and growing surface.…”