Effects of H coverage on Ge segregation during Si{sub 1{minus}x}Ge{sub x} gas-source molecular beam epitaxy

Journal Article · Mon Dec 01 04:00:00 EST 1997 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.366474· OSTI ID:550448

Kim, H; Taylor, N; Abelson, J R; Greene, J E ^[1]

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1. Materials Science Department, the Coordinated Science Laboratory, and the Materials Research Laboratory, University of Illinois, 1101 West Springfield Avenue, Urbana, Illinois 61801 (United States)

The effects of H coverage {theta}{sub H} on Ge segregation during Si{sub 1{minus}x}Ge{sub x} gas-source molecular beam epitaxy (GS-MBE) were investigated using D{sub 2} temperature programmed desorption (TPD). Si{sub 1{minus}x}Ge{sub x} films with x=0.01{endash}0.30 were grown from Si{sub 2}H{sub 6}/Ge{sub 2}H{sub 6} mixtures at T{sub s}=450{endash}800{degree}C, held at the growth temperature for 30 s, cooled to {lt}200{degree}C, and then exposed to atomic deuterium until saturation coverage. D{sub 2} TPD spectra were fit using four peaks corresponding, in order of decreasing activation energy, to desorption from Si monodeuteride, Ge{endash}Si mixed-dimer monodeuterides, Si dideuteride, and Ge monodeuteride. Steady-state Ge surface coverages were determined from the TPD data as a function of T{sub s} and x. In contrast to solid-source MBE films grown in this temperature regime, Ge segregation during GS-MBE decreases with decreasing T{sub s} due to the increasing H coverage. The results were well described by a model accounting for the Si/Ge site exchange and {theta}{sub H}. The Ge segregation enthalpy varies from {minus}0.28eV at T{sub s}{ge}800{degree}C, where the steady-state hydrogen coverage {theta}{sub H} approaches zero, to {minus}0.10eV at T{sub s}{le}450{degree}C, where {theta}{sub H} is nearly saturated. {copyright} {ital 1997 American Institute of Physics.}

• Research Organization: University of Illinois
• DOE Contract Number: AC02-76ER01198
• OSTI ID: 550448
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 12 Vol. 82; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
DESORPTION
ENTHALPY
GERMANIUM SILICIDES
HYDROGEN
MOLECULAR BEAM EPITAXY
SEGREGATION
SEMICONDUCTOR MATERIALS
TEMPERATURE DEPENDENCE
THIN FILMS