| Summary: | 碩士 === 國立中興大學 === 材料科學與工程學系所 === 98 === With the increasing miniaturization of the dimensions of integrated devices, Ni-silicide is a promising material for complementary metal-oxide-semiconductor (CMOS) devices because NiSi has a low resistivity, line-width-independent sheet resistance and low silicon consumption.
Many researchers have reported that a high thermal stability or a uniform Ni-silicide layer was formed by the addition of impurity, interlayer and capping layer. In this study, Ni-P films were deposited on Si (100) substrates by sputtering. Then Ni-silicide layers were formed by solid-phase reaction in Ni-P/Si (100) systems. Ni-silicide layers were prepared with various thicknesses to study the interface reactions, structures and electronic properties.
The results show as follows. For the 8-nm Ni-P/Si (100) system, a stable films were formed at the annealing temperature of as low as 400℃. Thus, the temperature of silicide films agglomerated increased from 500℃ to 750℃. At 700℃ annealing, a continuous NiSi2 layer with atomic flat interface and low grain boundary density was formed. The sheet resistance was decreased due to the reduction of the grain boundary and interface scattering for the conduction electrons. For the 20-nm Ni-P/Si (100) system, the low-resistivity window shifted towards the high temperature about 100℃. For 40-nm Ni-P/Si (100) system, the thermal stability of Ni-silicide films was similar to the 20-nm Ni-P/Si (100) system. However, because of the addition of P atoms the lattice constant of NiSi2 reduced, which causes the increasing of the lattice mismatch of NiSi2 and Si. The phenomenon leaded to the formation of a polycrystalline NiSi2 films.
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