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InP(110) interface formation
A610 Surface Science 162 (1985) 657-662 North-Holland, Amsterdam EPITAXIAL
GROWTH
OF
657 PLATINUM
SILICIDE
LAYERS
and Ming-Pang
LIN
ON
(111) Si
SUBSTRATES Jiann-Ruey
CHEN
*, T i a n - S h y n g
HEH
**
Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu, Taiwan 300, Rep. of China Received 1 April 1985; accepted for publication 10 May 1985 Epitaxial growth of PtSi on (1 l l)Si substrate was investigated for various substrate temperatures during Pt deposition and for various annealing procedures. Intermixing between Pt and Si was observed in the as-deposited films if Pt was deposited with substrate at elevated temperatures. If the substrate was kept at 330°C during deposition, PtSi in fiberous texture structure was observed in the as-deposited films. Epitaxial PtSi layer was formed after annealing at 385°C for 1 h followed by annealing at 550°C for 2 h. The formed PtSi thin films possess a strong degree of preferred orientation with a threefold position of different grains on the (111)Si substrate. Two sets of Moir6 fringes were observed with spacings 19.0 and 30.7 ~., corresponding to the interferences of {220)s , reflections with (301) Ptsi and (002) PtSi, respectively.
Surface Science 162 (1985) 663-670 North-Holland, A m s t e r d a m INVESTIGATION P. M A I G N I ~ ,
OF THE
C.A. SI~BENNE
663 Ag/lnP(ll0)
INTERFACE
FORMATION
*
and A. TALEB-IBRAHIMI
Laboratoire de Physique des Solides, associb au CNRS, Unioersitb Pierre et Marie Curie, F-75230 Paris Cbdex 05, France Received 1 April 1985; accepted for publication 4 April 1985 Photoemission yield spectroscopy (PYS), low energy electron diffraction (LEED) and Auger electron spectroscopy (AES) measurements are performed on a set of U H V cleaved InP(ll0) surfaces from n- and p-type crystals as a function of Ag coverage 0 which is varied from about 10-3 monolayer (ML) to 100 ML. Ag is shown to form an abrupt interface and no pseudo epitaxy of Ag is observed below 100 ML. The variations upon interface formation of the atomic structure, the work function ~, the ionization energy • and the semiconductor band bending are analysed together with the changes of the density of filled surface states in the gap and in the valence band within about 0.6 eV from the top. The pinning of the Fermi level observed on n-type samples at = 4.8 eV, giving then a band bending of 0.35 eV, and the decrease of the work function on p-type samples with 0 are related to the observed interface states the possible origin of which is discussed and compared to the A g - G a A s ( l l 0 ) system.
GROWTH
OF
657 PLATINUM
SILICIDE
LAYERS
and Ming-Pang
LIN
ON
(111) Si
SUBSTRATES Jiann-Ruey
CHEN
*, T i a n - S h y n g
HEH
**
Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu, Taiwan 300, Rep. of China Received 1 April 1985; accepted for publication 10 May 1985 Epitaxial growth of PtSi on (1 l l)Si substrate was investigated for various substrate temperatures during Pt deposition and for various annealing procedures. Intermixing between Pt and Si was observed in the as-deposited films if Pt was deposited with substrate at elevated temperatures. If the substrate was kept at 330°C during deposition, PtSi in fiberous texture structure was observed in the as-deposited films. Epitaxial PtSi layer was formed after annealing at 385°C for 1 h followed by annealing at 550°C for 2 h. The formed PtSi thin films possess a strong degree of preferred orientation with a threefold position of different grains on the (111)Si substrate. Two sets of Moir6 fringes were observed with spacings 19.0 and 30.7 ~., corresponding to the interferences of {220)s , reflections with (301) Ptsi and (002) PtSi, respectively.
Surface Science 162 (1985) 663-670 North-Holland, A m s t e r d a m INVESTIGATION P. M A I G N I ~ ,
OF THE
C.A. SI~BENNE
663 Ag/lnP(ll0)
INTERFACE
FORMATION
*
and A. TALEB-IBRAHIMI
Laboratoire de Physique des Solides, associb au CNRS, Unioersitb Pierre et Marie Curie, F-75230 Paris Cbdex 05, France Received 1 April 1985; accepted for publication 4 April 1985 Photoemission yield spectroscopy (PYS), low energy electron diffraction (LEED) and Auger electron spectroscopy (AES) measurements are performed on a set of U H V cleaved InP(ll0) surfaces from n- and p-type crystals as a function of Ag coverage 0 which is varied from about 10-3 monolayer (ML) to 100 ML. Ag is shown to form an abrupt interface and no pseudo epitaxy of Ag is observed below 100 ML. The variations upon interface formation of the atomic structure, the work function ~, the ionization energy • and the semiconductor band bending are analysed together with the changes of the density of filled surface states in the gap and in the valence band within about 0.6 eV from the top. The pinning of the Fermi level observed on n-type samples at = 4.8 eV, giving then a band bending of 0.35 eV, and the decrease of the work function on p-type samples with 0 are related to the observed interface states the possible origin of which is discussed and compared to the A g - G a A s ( l l 0 ) system.