Low temperature iron thin film-silicon reactions

Silicide formation in contacts to Si nanowires

“…The monosilicide is reported to form between 300 and 500°C. The temperature at which FeSi transforms to b-FeSi 2 is also shown to be dependent on the thickness of iron, with reported values ranging from 600 up to 800°C [35][36][37]40]. The formation of FeSi is diffusion controlled, whereas b-FeSi 2 is nucleation controlled [35,37,42].…”

“…In both cases, the oxide is found to inhibit the growth of silicides at room temperatures, but silicides still form at temperatures of 450-580°C. In studies without the oxide, silicon was found to be the dominate diffusing species [32,35,39]. On the other hand, it was found that SiO x acts as a diffusion barrier to silicon, which allows the diffusion of iron to become dominant.…”

“…Other studies show that FeSi is the initial silicide to form, with b-FeSi 2 forming second [35,36,40]. The monosilicide is reported to form between 300 and 500°C.…”

“…Formation temperature ranges varied from: 450 to 600°C for Fe 3 Si, 500 to 700°C for FeSi, and 550 to 750°C for b-FeSi 2 . Reports for the growth of Fe 3 Si range after the Fe pad is consumed [35], in mixed phases with other silicides [38], to not forming at all [39][40][41]. Lau et al reported the formation of Fe 3 Si from solid solution via a disorder-order transition [32].…”

“…There is some controversy in the literature over which phase forms first [32][33][34][35][36] for thin iron films on bulk silicon substrates (t [ 20 nm). In some cases, it is reported that Fe 3 Si forms first from an iron-silicon solid solution, followed by FeSi and then b-FeSi 2 by subsequent annealing at higher temperatures [32,37].…”