Study of cobalt-disilicide formation from cobalt monosilicide

Abstract

The reaction CoSi+Si→CoSi2 has been investigated in the temperature range of 500–600 °C, using Rutherford backscattering, x-ray diffraction, transmission electron microscopy, and four-point sheet-resistance measurements. The reaction is very slow at 500 °C and extremely fast at 600 °C, and appears to occur in four stages: (a) nucleation of the CoSi2 phase at the grain-boundary triple points, (b) lateral growth from nucleation sites to form a continuous layer on the silicon surface, (c) growth in thickness by diffusion through this disilicide layer, and (d) the lateral epitaxial growth by eliminating the grain boundaries. The diffusion through the disilicide layer seems to be a rate-limiting process with high activation energy.

Growth of single-crystalline cobalt silicide nanowires with excellent physical properties

“…The nucleation rate of NWs will be proportional to the concentration of Si. 27 Thus, the density of CoSi nanowires increases as the pressure increases. However, it tends to form bulk morphology when pressure is too high.…”

“…For higher ambient pressure, the aspect ratio become larger with decreasing [Co]=[Si] compositions. 27 In addition, the ambient pressure will not change the phase of the NWs. The highresolution TEM image ( Fig.…”

“…Next, with the increase of the temperature, the Co 2 Si thin film with nanoparticles on the top would transform to CoSi, which is the thermodynamically most stable phase in the reaction of Si substrate and CoCl 2 . 27 Finally, the single crystalline CoSi NWs grow by self-catalyzing. In our results, there is no catalyst on the top of the NWs.…”

Enhanced growth of low-resistivity cobalt silicide by using a Co/Au/Co trilayer film on Si0.8Ge0.2 virtual substrate

“…For the growth of CoSi 2 , it is well known that the CoSi 2 is formed via a nucleation-controlled reaction mechanism [13]. According to the classical nucleation theory, the activation energy for nucleation DG* is proportional to [Ds 3 /DG 2 ], with DG = DH À TDS [14,15].…”

Investigation of solid reaction between Fe and Si0.8Ge0.2

“…d'Heurle et al have proposed a mathematical model based on the activation energy theory for this process [14,15]. Furthermore, previous studies have proposed that the different solubility of foreign elements during silicide formation may influence the nucleation process [16,17]. From the AES and EDS analysis shown in Fig.…”