Ni silicides formation and properties in RF sputtered Ni 100− xSi x thin films

• Published in: Applied surface science Vol. 91; no. 1; pp. 63 - 67
• Main Authors: Belu-Marian, Aretia, Serbanescu, M.D., Manaila, Rodica, Devenyi, A.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.10.1995
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/0169-4332(95)00095-X

The temperature dependence of the electrical resistance R( T) for RF sputtered Ni 100− x Si x thin films (33 ≤ x ≤ 56 as determined by Rutherford backscattering spectroscopy) was measured between −190°C and the annealing temperature T a ( T a max = 300° C). Structure investigations by X-ray diffraction revealed the preferential formation of silicide phases in as-deposited films as dependent on composition: γ-Ni 5Si 2 (for x = 33), δ-Ni 2Si (37 ≤ x ≤ 40) and Д-NiSi 2 (for x = 56). For intermediary compositions, amorphous alloys are formed. Annealing at 200 and 300°C induces crystallization of the amorphous films into the γ-Ni 5Si 2 phase (with Д-NiSi 2 admixture). The preferential formation of silicide phases is discussed taking into account the phenomenological rule of “effective formation heat”. The temperature dependence of electrical resistance for as-deposited and annealed γ and δ polycrystalline silicide thin films exhibits a classic metallic behaviour (different from that of polycrystalline Ni thin films). The very different R( T) behaviour of as-deposited and annealed polycrystalline Д-phase is interpreted taking into account the weak localization contribution.