Interfacial reactions in thin film and bulk iron/silicon couples

Conference · Tue Jul 01 04:00:00 EDT 1997

OSTI ID:20015542

Zhang, Y; Ivey, D G

Initial phase formation in thin film and bulk Fe/Si couples has been investigated using transmission and scanning electron microscopy (TEM and SEM). For the thin film couples, {approx}165 nm of Fe was deposited by electron beam evaporation onto <111> oriented Si substrates. SiO{sub 2} capping layers ({approx}100 nm thick) were used to protect the Fe from oxidation during subsequent annealing. Bulk diffusion couples were fabricated by clamping together polycrystalline Fe pieces and <111> oriented single crystal Si pieces and sealed in evacuated ({approx}10{sup {minus}4} torr) quartz capsules. Annealing of thin film couples was done at temperatures ranging from 300 C to 500 C for up to several hours. Bulk couples were annealed at 700 C for up to {approx}1,000 hrs. Interfacial reactions were detected in as deposited thin film couples. A layer {approx}5 nm thick was identified, through electron diffraction, as poorly crystalline off-stoichiometric Fe{sub 3}Si. Iron was the major diffuser during the formation of Fe{sub 3}Si. During annealing off-stoichiometric Fe{sub 3}Si transformed to stoichiometric Fe{sub 3}Si. FeSi was the next phase to form-initially detected after annealing at 300 C for 3 hrs. Similar results were obtained for bulk couples. The first phase to form was ordered stoichiometric Fe{sub 3}Si (initially detected after 7 hrs), followed by FeSi ({approx}23 hrs) and then FeSi{sub 2}(>200 hrs). The formation behavior of this phase is discussed.

• Research Organization: Univ. of Alberta, Edmonton, Alberta (CA)
• Sponsoring Organization: Natural Sciences and Engineering Research Council of Canada
• OSTI ID: 20015542
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CHEMICAL REACTIONS
COMPOSITE MATERIALS
DIFFUSION
EXPERIMENTAL DATA
INTERFACES
IRON
MICROSCOPY
PHASE STUDIES
SILICON
THIN FILMS