Role of the substrate strain in the sheet resistance stability of NiSi deposited on Si(100)

Abstract

In order to study the influence of strain on the formation and stability of NiSi, Ni has been deposited on strained and relaxed Si(100) n-type substrates. Strained Si substrates have been produced by depositing a pseudomorphic silicon film onto a 3000 Å thick relaxed Si0.8Ge0.2 film. Raman spectroscopy has established that the silicon film is strained. The presence of a characteristic cross-hatch pattern has been identified by atomic force microscopy. Measurements show that the sheet resistance (Rs) of the silicide formed on strained silicon remains stable up to 700 °C while the Rs of the silicide formed on bulk silicon (100) shows a significant increase at 600 °C . X-ray photoelectron spectroscopy shows that the NiSi–NiSi2 phase transition occurs at a higher temperature and is, therefore, not responsible for the Rs instability. Scanning electron microscopy measurements indicate that islanding occurs in the temperature region of the resistivity increase. Photoelectron emission microscopy has been employed to observe the surface morphology during annealing, and islanding is not observed until a higher annealing temperature for the NiSi on strained Si. The increase in Rs is apparently correlated to the islanding of NiSi which appears at lower temperature on the bulk silicon substrate than on the strained silicon substrate. The stability of the NiSi film on the strained Si substrate is related to the strain induced by thermal expansion and the increased lattice constant of the strained Si.

High-resolution transmission electron microscopy of silicide formation and morphology development of Ni/Si and Ni/Si1−xGex

“…[7][8][9][10]16 Thus, nonequilibrium phases at different stages, such as those described later, may form and be metastably retained at room temperature. By heating quickly to 900°C, a temperature at which NiSi is not stable, NiSi 2 is free to nucleate at random locations on a clean Ni/Si interface and grow by fast Ni diffusion through the NiSi 2 lattice via a vacancy mechanism.…”

“…[7][8][9][10] In the ternary Ni/Si 1-x Ge x system, the phase reactions and morphological transformations are still more complicated. Island structures and Ge segregation have been observed following high-temperature annealing treatments.…”

Thermal Stability of Nickel Germanide Formed on Tensile-Strained Ge Epilayer on Si Substrate

“…Agglomeration depends on the surface energies of the substrate and the overlayer, including the strain energy. The lattice mismatch will play an important role [12]. For the coefficient of thermal expansion of Ge is larger than that of Si, the tensile strain in Ge-onSi with a low-temperature Ge buffer increasing linearly with the annealing temperature has been demonstrated [13].…”

Heavy ion induced modifications on morphological, magnetic and magneto-transport behaviour of exchange-biased Fe/NiO and NiO/Fe bilayers with Si substrate for spintronic applications

“…positions at 855.0 and 857.8 eV (Fig. 8a-i) seem to correspond to the silicide phase of nickel, NiSi 2 [40] along with a satellite peak at 862.4 eV (Fig. 8a-ii).…”