Abstract
The phase formation and stability of CoSi2 on strained epitaxial Si0.80Ge0.20/Si (0 0 1) thin films has been investigated. Silicide films prepared via direct deposition of cobalt (Co/SiGe), and via co-deposition of silicon and cobalt (Co+2Si/SiGe), were compared. EXAFS, XRD, and sheet-resistance measurements indicated that co-deposited Co+2Si films annealed at 400-700°C exhibit the expected low-resistivity CoSi2 structure but were susceptible to roughening, pinhole formation, and agglomeration. In contrast, the Co/SiGe structure formed CoSi2 only after annealing at 700°C and suicide formation was accompanied by Ge segregation in the contact region. In situ RHEED experiments indicated that growth of CoSi2 co-deposited on SiGe at 400-500°C results in immediate island formation. Template methods, which are often used to enhance the quality of co-deposited Co+2Si/Si structures, did not lead to two-dimensional growth in the Co+2Si/SiGe system. In situ EXAFS measurements of 2 A Co films deposited on SiGe substrates and annealed at 450°C suggested that the failure to achieve two-dimensional growth may be due to preferential bonding of Co to Si atoms at the interface, which prevents the formation of a continuous CoSi2 template.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 84-89 |
| Number of pages | 6 |
| Journal | Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms |
| Volume | 133 |
| Issue number | 1-4 |
| State | Published - Dec 2 1997 |
| Externally published | Yes |
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Keywords
- Cobalt silicide
- Metal-semiconductor contacts
- Molecular beam epitaxy
- Silicon germanium alloys
ASJC Scopus subject areas
- Surfaces, Coatings and Films
- Instrumentation
- Surfaces and Interfaces
Cite this
Structure and stability of cobalt-silicon-germanium thin films. / Goeller, Peter T.; Boyanov, Boyan I.; Savers, Dale E.; Nemanich, Robert.
In: Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms, Vol. 133, No. 1-4, 02.12.1997, p. 84-89.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Structure and stability of cobalt-silicon-germanium thin films
AU - Goeller, Peter T.
AU - Boyanov, Boyan I.
AU - Savers, Dale E.
AU - Nemanich, Robert
PY - 1997/12/2
Y1 - 1997/12/2
N2 - The phase formation and stability of CoSi2 on strained epitaxial Si0.80Ge0.20/Si (0 0 1) thin films has been investigated. Silicide films prepared via direct deposition of cobalt (Co/SiGe), and via co-deposition of silicon and cobalt (Co+2Si/SiGe), were compared. EXAFS, XRD, and sheet-resistance measurements indicated that co-deposited Co+2Si films annealed at 400-700°C exhibit the expected low-resistivity CoSi2 structure but were susceptible to roughening, pinhole formation, and agglomeration. In contrast, the Co/SiGe structure formed CoSi2 only after annealing at 700°C and suicide formation was accompanied by Ge segregation in the contact region. In situ RHEED experiments indicated that growth of CoSi2 co-deposited on SiGe at 400-500°C results in immediate island formation. Template methods, which are often used to enhance the quality of co-deposited Co+2Si/Si structures, did not lead to two-dimensional growth in the Co+2Si/SiGe system. In situ EXAFS measurements of 2 A Co films deposited on SiGe substrates and annealed at 450°C suggested that the failure to achieve two-dimensional growth may be due to preferential bonding of Co to Si atoms at the interface, which prevents the formation of a continuous CoSi2 template.
AB - The phase formation and stability of CoSi2 on strained epitaxial Si0.80Ge0.20/Si (0 0 1) thin films has been investigated. Silicide films prepared via direct deposition of cobalt (Co/SiGe), and via co-deposition of silicon and cobalt (Co+2Si/SiGe), were compared. EXAFS, XRD, and sheet-resistance measurements indicated that co-deposited Co+2Si films annealed at 400-700°C exhibit the expected low-resistivity CoSi2 structure but were susceptible to roughening, pinhole formation, and agglomeration. In contrast, the Co/SiGe structure formed CoSi2 only after annealing at 700°C and suicide formation was accompanied by Ge segregation in the contact region. In situ RHEED experiments indicated that growth of CoSi2 co-deposited on SiGe at 400-500°C results in immediate island formation. Template methods, which are often used to enhance the quality of co-deposited Co+2Si/Si structures, did not lead to two-dimensional growth in the Co+2Si/SiGe system. In situ EXAFS measurements of 2 A Co films deposited on SiGe substrates and annealed at 450°C suggested that the failure to achieve two-dimensional growth may be due to preferential bonding of Co to Si atoms at the interface, which prevents the formation of a continuous CoSi2 template.
KW - Cobalt silicide
KW - Metal-semiconductor contacts
KW - Molecular beam epitaxy
KW - Silicon germanium alloys
UR - http://www.scopus.com/inward/record.url?scp=0031550024&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0031550024&partnerID=8YFLogxK
M3 - Article
VL - 133
SP - 84
EP - 89
JO - Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms
JF - Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms
SN - 0168-583X
IS - 1-4
ER -