UCLA

In my research, there are two structures for silicidation by solid state reaction. The lateral structures and full coverage of NWs are utilized to study the formation and electrical properties of NiSi2 NWs. By the lateral structure, we can know that NiSi2 wins as the first phase, but the length of NiSi2 is not long enough for electrical measurements. Therefore, a new structure is adopted for create long and pristine NiSi2 NWs. Ni is global deposited onto the top of Si NWs, and an ALD Al2O3 shell is applied to confine the expansion of NWs during phase transformation. The thicker nickel film can provide more Ni source on all the NWs, and thicker of oxide film can increase the compressive stress and confine the volume expansion during annealing process. The thickness of Ni and Al2O3 as well as the annealing temperature has been studied in this research. The long and pristine NiSi2 NW can be formed successfully inaSiNWwith15nmNianda29nmAl2O3 shellat650°Cforannealing30min. The four terminal resistivity of a 52 nm NiSi2 NW is 39.2 μΩ-cm, and the current density is 2.6×107 A/cm2.