Low-Temperature Fabrication of Polycrystalline Si Thin Film Using Al-Induced Crystallization without Native Al Oxide at Amorphous Si/Al Interface

Abstract

Low-temperature fabrication of polycrystalline silicon (poly-Si) thin film has been performed by Al-induced crystallization (AIC), and the structural properties have been investigated. In our experiments, to prevent native oxidation of Al film, an amorphous silicon (a-Si)/Al bilayer was formed on the SiO2/Si substrate by electron beam evaporation without breaking the vacuum. The a-Si/Al/SiO2/Si structure was then heated at a low temperature of 400°C to induce AIC. It was confirmed that layer exchange of the a-Si/Al bilayer is induced even though there is no native oxidation of Al film, which was demonstrated by scanning transmission electron microscopy and energy dispersive X-ray analysis. The mechanism for layer exchange of the a-Si/Al bilayer has been discussed. Furthermore, it was verified by scanning electron microscopy and spectroscopic ellipsometry that the a-Si/Al thickness ratio of roughly 1:1 is suitable to achieve a flat surface morphology of poly-Si. In addition, it was found, by X-ray diffraction and orientation imaging microscopy, that the Si(111)-oriented grain becomes dominant with decreasing thickness of the a-Si/Al bilayer.

Minority carrier lifetime of thin polycrystalline silicon nanowire films on polycrystalline silicon layer prepared by aluminum-induced crystallization

“…Figure 2 (b) also shows that the grain size of the AIC poly-Si layer prepared from the same a-Si and Al thickness is larger than 10 m. This result is in good agreement with the previously reported results 20 . Figure 3 shows Raman spectra of AIC poly-Si layers prepared at a temperature ranging from 450 to 525 o C. The thicknesses of the a-Si and Al are 200 nm.…”

Dependence of crystal orientation in Al-induced crystallized poly-Si layers on SiO2 insertion layer thickness

“…On the other hand, growth of (111)-oriented Si layers has been also reported [15,18]. Kurosawa et al showed that the preferential orientation of AIC-Si on fused silica can be controlled by changing the exposure time of Al in air, and they proposed a model showing that the orientation of AIC-Si is determined by the crystal phase of the native Al oxide [19].…”

Impact of amorphous Ge thin layer at the amorphous Si/Al interface on Al-induced crystallization

“…In the case of Si, isothermal annealing of amorphous Si (a-Si)/Al layers on glass at temperatures below the eutectic temperature (577 1 C) results in layer exchange and formation of a continuous polycrystalline Si thin film [2][3][4][5].The preferential growth orientation is known to be either /1 0 0S or /1 1 1S depending on growth conditions [6][7][8][9].…”