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Si interface formation studied by photoemission
A71 Surface Science 210 (1989) 85-98 North-Holland, Amsterdam
85
XPS AND XRD INVESTIGATIONS
OF Dy/Si
Shubha GOKHALE,
Shailaja MAHAMUNI
V.J. R A O
Nehal AHMED,
* *, A.S. N I G A V E K A R
INTERFACE *,
a n d S.K. K U L K A R N I
Department of Pl~vsics, University of Poona, Pune 411 007, India Received 6 June 1988; accepted for publication 28 October 1988 The interaction of dysprosium metal atoms with silicon (111) surface at different temperatures has been investigated using X-ray photoelectron spectroscopy and X-ray diffraction analysis. Si 2p and Dy 3d5/2 spectral lines are used to propose the Dy-Si interaction in the interface region. Even at room temperature (300 K) strong interaction between Dy and Si atoms takes place due to charge transfer from Dy to Si. At this temperature, at the interface, a predominantly Dy-rich DysSi 3 phase is observed. Whereas at an annealing temperature of 623 K a silicon-rich DySi2 phase is observed. At an intermediate temperature of 423 K both these phases are seen with some amorphous background.
Surface Science 210 (1989) 99-113 North-Holland, Amsterdam MECHANISM
OF THE Y/Si
99 INTERFACE
FORMATION
S T U D I E D BY P H O T O E M I S S I O N A. P E L L I S S I E R ,
R. B A P T I S T
Division LET1/DOPT, CENG, 85X, F-38041 Grenoble Cedex, France and G. CHAUVET
DRF, G/Service de Physique, PSC, CENG, 85X, F-38041 Grenoble Cedex, France Received 29 June 1988; accepted for publication 31 October 1988 XPS and UPS analyses have been used to study the Y/Si interface, obtained by deposition of yttrium atoms on a clean silicon surface. They reveal a three-step-mechanism of formation, at room temperature. First, a pure yttrium thin layer forms. Then, when the Y thickness reaches roughly two monolayers, the abrupt interface becomes unstable and Si atoms diffuse through the yttrium. The resulting Si concentration is roughly 5-7 at% if the Si atoms are distributed in a homogeneous way over the whole yttrium overlayer. Finally, above four monolayers, metallic yttrium grows.
85
XPS AND XRD INVESTIGATIONS
OF Dy/Si
Shubha GOKHALE,
Shailaja MAHAMUNI
V.J. R A O
Nehal AHMED,
* *, A.S. N I G A V E K A R
INTERFACE *,
a n d S.K. K U L K A R N I
Department of Pl~vsics, University of Poona, Pune 411 007, India Received 6 June 1988; accepted for publication 28 October 1988 The interaction of dysprosium metal atoms with silicon (111) surface at different temperatures has been investigated using X-ray photoelectron spectroscopy and X-ray diffraction analysis. Si 2p and Dy 3d5/2 spectral lines are used to propose the Dy-Si interaction in the interface region. Even at room temperature (300 K) strong interaction between Dy and Si atoms takes place due to charge transfer from Dy to Si. At this temperature, at the interface, a predominantly Dy-rich DysSi 3 phase is observed. Whereas at an annealing temperature of 623 K a silicon-rich DySi2 phase is observed. At an intermediate temperature of 423 K both these phases are seen with some amorphous background.
Surface Science 210 (1989) 99-113 North-Holland, Amsterdam MECHANISM
OF THE Y/Si
99 INTERFACE
FORMATION
S T U D I E D BY P H O T O E M I S S I O N A. P E L L I S S I E R ,
R. B A P T I S T
Division LET1/DOPT, CENG, 85X, F-38041 Grenoble Cedex, France and G. CHAUVET
DRF, G/Service de Physique, PSC, CENG, 85X, F-38041 Grenoble Cedex, France Received 29 June 1988; accepted for publication 31 October 1988 XPS and UPS analyses have been used to study the Y/Si interface, obtained by deposition of yttrium atoms on a clean silicon surface. They reveal a three-step-mechanism of formation, at room temperature. First, a pure yttrium thin layer forms. Then, when the Y thickness reaches roughly two monolayers, the abrupt interface becomes unstable and Si atoms diffuse through the yttrium. The resulting Si concentration is roughly 5-7 at% if the Si atoms are distributed in a homogeneous way over the whole yttrium overlayer. Finally, above four monolayers, metallic yttrium grows.