The crystallization behavior of a-Si:H/Ag/a-Si:H sandwich films has been studied in detail. Fractals of Si caused by metal enhanced crystallization appear after annealing at 350–600 °C. The fractal dimension decreases (the Si fractals become more open) with the increasing annealing temperature. The number density of fractals increases at 350–450 °C and turns to decrease at 500–600 °C. The average fractal size increases from 350 to 550 °C and shows a decreasing tendency at 600 °C. The formation of fractals can be explained by a random successive nucleation and growth model. The x-ray energy dispersive spectroscopy (EDS) microanalysis indicates that although there is lateral interdiffusion of Ag and Si atoms, the thicknesses of the fractal region and the matrix remain nearly the same. At the same time, EDS shows that there are also Ag aggregates extending out of the films. It is suggested that besides the preferred nucleation at the Ag/Si interface the break of Si—H bonds may also stimulate the crystallization of a-Si:H so that the crystallization temperature of an a-Si:H/Ag system is much lower than that of an a-Si/Ag system.
In situ TEM, TEM and Raman studies of the effect of heat treatment on the microstructural processes of an Al/a-SiC:H film have been undertaken. The TEM results show that the interface of the films is inert at room temperature, and that annealing below 350 degrees C does not cause a significant interfacial reaction. However, silicon precipitation occurs at a temperature of about 350 degrees C. Higher temperatures lead to the formation of the Al4C3 compound. Ultimately, the reaction products of the films are determined to be Al4C3 and silicon after annealing at 550 degrees C. Raman scattering results also confirm the formation and growth of Si crystallites.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.