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Theory of transition from the dihydride to the monohydride phase on the Si(001) surface
A638 Surface Science 178 (1986) 70-79 North-Holland, Amsterdam
70
CHEMICAL CHARACTERIZATION OF SUPERFICIAL LAYERS OF MONOCRYSTALLINE SILICON AFTER ANNEALING IN A RF HYDROGEN PLASMA D. BALLUTAUD Luhorutoire
de Ph_vsique des Solides, CNRS,
I Place A. Briand,
F-921 90 Meudon,
France
G. MOULIN Lcthorutoire
de M&allurgie
((/A
1107), lJnioersit6
Paris-Sud,
F-91405
Orsuy. France
and M. AUCOUTURIER Luhoratoire
Received
de Physique
14 March
des Solides, CNRS,
1986; accepted
1 Place A. Briund,
for publication
F-921 90 Meudon,
Frunce
24 May 1986
This work is part of a genera1 investigation on the physico-chemical behaviour of hydrogen in mono- and poly-crystalline silicon for photovoltaic purpose. Hydrogenation is carried out by annealing in a RF hydrogen plasma. Hydrogen concentration is measured by SIMS depth profiling of deuterium. The plasma-induced phenomena and the influence of charging conditions are studied in the near-surface region by X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES) and electron energy-loss spectroscopy microprobe (EELS). Using an argon 0 mill, the superficial layers are investigated up to 500 A deep. After the plasma exposure, an additional contamination (specially by carbon and oxygen) is observed in the first superficial layers. Subsequent ion milling leads to a clean region except for oxygen traces. The modification of the first- and second-derivative mode EELS spectra are investigated in connection with hydrogen and oxygen contents.
Surface Science 178 (1986) 80-89 North-Holland, Amsterdam
80
THEORY OF TRANSITION FROM THE DIHYDRIDE TO THE MONOHYDRIDE PHASE ON THE Si(OO1) SURFACE s. CIRACI IBM
*
Research Lnboratoty,
San Jose, California
95193,
USA
and Inder IBM
P. BATRA Zurich
Received
**
Research Loboratory,
13 March
1986; accepted
8803 Riischlikon,
for publication
Switzerland
16 June 1986
Recent studies have revealed interesting properties of the dihydride phase coexisting with the monohydride phase on the hydrogenated Si surfa,ces. In this work, we report self-consistent total-energy calculations within the framework of the local density functional theory, which provide a rigorous basis for understanding the transition between the dihydride and monohydride
A639 phases, and the desorption of hydrogen from Si surfaces. We found that the energy associated with the rotation of SiH, in the plane bisecting the angle between two back bonds is rather small. The equilibrium configuration is not the ideal SiHs which completes the tetrahedral coordination, and the total energy is lowered when all SiH, radicals are tilted in the same direction. The forces exerted on the atoms, as well as the results of the geometry optimization indicate that the outermost Si plane relaxes inwards even at full coverage of SiH2. The charge-density analysis shows how the H, bond is formed from the two adjacent SiH, radicals approaching each other.
Surface Science 178 (1986) 90-100 North-Holland, Amsterdam
90
HYDROGEN
INTERACTION
WITH SEMICONDUCTOR
SURFACES
J.A. SCHAEFER Fachbereich Physik, GH Kassel-Universitiit, Received
18 March
1986; accepted
D-3500 Kassel, Fed. Rep.
for publication
of German.*,
17 April 1986
This paper is a status report upon hydrogen interaction with surfaces of elemental semiconductors (Si), alloys (Ge,Si,_,) and III-V compound semiconductors (GaAs, InP). Primarily, highresolution electron energy-loss (HREELS) data are reported. It is shown that atomic hydrogen may be used as a marker for the determination of active sites on differently prepared semiconductor interfaces. For a more complete characterization of its local atomic structure, results from other surface sensitive techniques (LEED, Auger, XPS, SXPS) are included. In addition, systematic chemical shifts of Si- and Ge-hydrogen vibrational stretching modes were measured for different oxidation stages in the submonolayer range at Si(lO0) and at Ge,Si, _,(lOO) surfaces. The latter observations are explained by the electronegativity of the next- and second-nearest neighbors of the hydrogen atoms.
Surface Science 178 (1986) 101-109 North-Holland, Amsterdam
101
A PSID SEXAFS STUDY OF H,O ADSORPTION
ON Si(100)
R. McGRATH, LT. MCGOVERN Department
of Pure and Applied Physics, Trinity College, Dublin 2, Ireland
D.R. WARBURTON, G. THORNTON * Department
of Chemistry,
University of Manchester, Manchester Ml3 9PL. UK
and D. NORMAN SERC Daresbury Laboratory, Daresbury Received
18 March
1986; accepted
Warrington WA4 4AD, UK
for publication
The technique of photon stimulated ion been applied in a study of the Si(lOO)/H,O derived by comparison of the H + ion yield the Si(100) surface. Within the constraints bonding to the upper atom of an asymmetric Levine and the asymmetric model of Chadi.
26 June 1986
desorption (PSID) surface EXAFS (SEXAFS) has surface. Information on the Si surface geometry is Si K-edge SEXAFS data with theoretical models of of a single dimer model geometry and hydrogen dimer, the data favour both the symmetric model of
70
CHEMICAL CHARACTERIZATION OF SUPERFICIAL LAYERS OF MONOCRYSTALLINE SILICON AFTER ANNEALING IN A RF HYDROGEN PLASMA D. BALLUTAUD Luhorutoire
de Ph_vsique des Solides, CNRS,
I Place A. Briand,
F-921 90 Meudon,
France
G. MOULIN Lcthorutoire
de M&allurgie
((/A
1107), lJnioersit6
Paris-Sud,
F-91405
Orsuy. France
and M. AUCOUTURIER Luhoratoire
Received
de Physique
14 March
des Solides, CNRS,
1986; accepted
1 Place A. Briund,
for publication
F-921 90 Meudon,
Frunce
24 May 1986
This work is part of a genera1 investigation on the physico-chemical behaviour of hydrogen in mono- and poly-crystalline silicon for photovoltaic purpose. Hydrogenation is carried out by annealing in a RF hydrogen plasma. Hydrogen concentration is measured by SIMS depth profiling of deuterium. The plasma-induced phenomena and the influence of charging conditions are studied in the near-surface region by X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES) and electron energy-loss spectroscopy microprobe (EELS). Using an argon 0 mill, the superficial layers are investigated up to 500 A deep. After the plasma exposure, an additional contamination (specially by carbon and oxygen) is observed in the first superficial layers. Subsequent ion milling leads to a clean region except for oxygen traces. The modification of the first- and second-derivative mode EELS spectra are investigated in connection with hydrogen and oxygen contents.
Surface Science 178 (1986) 80-89 North-Holland, Amsterdam
80
THEORY OF TRANSITION FROM THE DIHYDRIDE TO THE MONOHYDRIDE PHASE ON THE Si(OO1) SURFACE s. CIRACI IBM
*
Research Lnboratoty,
San Jose, California
95193,
USA
and Inder IBM
P. BATRA Zurich
Received
**
Research Loboratory,
13 March
1986; accepted
8803 Riischlikon,
for publication
Switzerland
16 June 1986
Recent studies have revealed interesting properties of the dihydride phase coexisting with the monohydride phase on the hydrogenated Si surfa,ces. In this work, we report self-consistent total-energy calculations within the framework of the local density functional theory, which provide a rigorous basis for understanding the transition between the dihydride and monohydride
A639 phases, and the desorption of hydrogen from Si surfaces. We found that the energy associated with the rotation of SiH, in the plane bisecting the angle between two back bonds is rather small. The equilibrium configuration is not the ideal SiHs which completes the tetrahedral coordination, and the total energy is lowered when all SiH, radicals are tilted in the same direction. The forces exerted on the atoms, as well as the results of the geometry optimization indicate that the outermost Si plane relaxes inwards even at full coverage of SiH2. The charge-density analysis shows how the H, bond is formed from the two adjacent SiH, radicals approaching each other.
Surface Science 178 (1986) 90-100 North-Holland, Amsterdam
90
HYDROGEN
INTERACTION
WITH SEMICONDUCTOR
SURFACES
J.A. SCHAEFER Fachbereich Physik, GH Kassel-Universitiit, Received
18 March
1986; accepted
D-3500 Kassel, Fed. Rep.
for publication
of German.*,
17 April 1986
This paper is a status report upon hydrogen interaction with surfaces of elemental semiconductors (Si), alloys (Ge,Si,_,) and III-V compound semiconductors (GaAs, InP). Primarily, highresolution electron energy-loss (HREELS) data are reported. It is shown that atomic hydrogen may be used as a marker for the determination of active sites on differently prepared semiconductor interfaces. For a more complete characterization of its local atomic structure, results from other surface sensitive techniques (LEED, Auger, XPS, SXPS) are included. In addition, systematic chemical shifts of Si- and Ge-hydrogen vibrational stretching modes were measured for different oxidation stages in the submonolayer range at Si(lO0) and at Ge,Si, _,(lOO) surfaces. The latter observations are explained by the electronegativity of the next- and second-nearest neighbors of the hydrogen atoms.
Surface Science 178 (1986) 101-109 North-Holland, Amsterdam
101
A PSID SEXAFS STUDY OF H,O ADSORPTION
ON Si(100)
R. McGRATH, LT. MCGOVERN Department
of Pure and Applied Physics, Trinity College, Dublin 2, Ireland
D.R. WARBURTON, G. THORNTON * Department
of Chemistry,
University of Manchester, Manchester Ml3 9PL. UK
and D. NORMAN SERC Daresbury Laboratory, Daresbury Received
18 March
1986; accepted
Warrington WA4 4AD, UK
for publication
The technique of photon stimulated ion been applied in a study of the Si(lOO)/H,O derived by comparison of the H + ion yield the Si(100) surface. Within the constraints bonding to the upper atom of an asymmetric Levine and the asymmetric model of Chadi.
26 June 1986
desorption (PSID) surface EXAFS (SEXAFS) has surface. Information on the Si surface geometry is Si K-edge SEXAFS data with theoretical models of of a single dimer model geometry and hydrogen dimer, the data favour both the symmetric model of