In situ Study of the Formation of Silicide Phases in Amorphous Ni-Si Mixed Layers
In this paper, we investigated Ni silicide phase formation when Si is added within an as deposited 50 nm Ni film. A series of 22 samples with a Si content varying from 0 to 50 at.% was prepared and systematically investigated with in situ x-ray diffraction. The inert oxide substrate was used to identify the phases which first crystallize in an amorphous Ni-Si mixture of a given concentration. The noncongruent silicides Ni{sub 3}Si and Ni{sub 3}Si{sub 2} are never observed to crystallize readily out of the mixture. A remarkable observation is the initial crystallization at low temperature of a hexagonal Ni-silicide, observed over a broad mixed layer composition [35-49%Si]; this hexagonal phase nucleates readily as a single phase [39-47%Si] or together with Ni{sub 2}Si [35-38%Si] or NiSi [49%Si]. This low-temperature phase is related to the high temperature {theta}-phase, but covers a wide composition range up to 47%Si. For the same Ni-Si films deposited on Si(100), the initial nucleation of the Ni(Si) mixture is similar as for the samples deposited on SiO{sub 2}, such that the complex sequence of metal-rich Ni-silicide phases typically observed during Ni/Si reactions is modified. For samples containing more than 21%Si, a simpler sequential phase formation was observed upon annealing. From pole figures, the phase formation sequence was observed to have a significant influence on the texture of the technologically relevant NiSi phase. For mixture composition ranging from 38% to 43%Si, the initial transient {theta}-phase appears extremely textured on Si(100). The observed transient appearance of a hexagonal phase is of importance in understanding the phase formation mechanisms in the Ni-Si system.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States). National Synchrotron Light Source
- Sponsoring Organization:
- DOE - OFFICE OF SCIENCE
- DOE Contract Number:
- DE-AC02-98CH10886
- OSTI ID:
- 1019773
- Report Number(s):
- BNL-95619-2011-JA; JAPIAU; TRN: US201115%%412
- Journal Information:
- Journal of Applied Physics, Vol. 106, Issue 6; ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
Similar Records
Improvement of the thermal stability of nickel silicide using a ruthenium interlayer deposited via remote plasma atomic layer deposition
Metastable Phase Formation During the Reaction of Ni Films with Si(001): the Role of Texture Inheritance