| Summary: | 碩士 === 國立中央大學 === 電機工程學系 === 102 === We reported the experimental discoveries of geometrical volume expansion, crystallographic morphology/phase formation, electromigration and electrical resistivity of nickel silicide nanowires(NWs) strongly dependent on the geometrical size of the initially-formed single-crystalline Si (c-Si) and poly-crystalline Si (poly-Si) NWs before silicidation. There appear to have three different distinctive NWs size ranges of 200-500, 100-200 and 75-100nm-wide c-Si NWs for the generation of Ni3Si2, Ni2Si and Ni31Si12 NWs, respectively, that are generated after silicidation at of c-Si NWs 500 oC. The factor of multiple phases for NixSiy NWs formed by silicidation at 500 oC makes a distinct contrast to the single phase formation of NiSi for bulk Si silicidation at 500 oC. This reveals a c-Si NWs with a higher aspect ratio provides an additional sidewalls for accommodating the volume expansion, leading to N-rich phases instead of silicon-rich phases.
We also report the electromigration and electrical reliability of nickel polycide NWs made from fully silicidation (FUSI) of poly-crystalline Si (poly-Si) NWs. Following electrical stressing that ultimately made a nickel silicide NWs rupture due to local self-heating and electromigration of the nickel silicide NWs, a unique migration of nickel polycide NWs facilitates solid state reactions with Si3N4 layer in close proximity to them. Nickel polycide interacted with Si that is released form the dissociation of Si3N4, making the phase transformation of nickel polycide NWs from nickel-rich to silicon-rich phase near the rupture locations.
After all, we reported the geometrical strain effect on phase formation, electromigration and rupture phenomenon of nickel silicide NWs providing a detailed databases of material stability and electrical reliability for the fabrication of electrode, local metal nanocontacts and connections for Si nanoelectronic devices.
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