The Institute of Scientific and Industrial Research, Osaka University, Mihogaoka, Ibaraki, Osaka 567-0047, Japan.
J Microsc. 2009 Nov;236(2):123-7. doi: 10.1111/j.1365-2818.2009.03270.x.
Formation processes of beta-FeSi(2) from amorphous Fe-Si layers have been investigated using transmission electron microscopy (TEM). Si(111) substrates were irradiated with 120 keV Fe ions at -150 degrees C to fluences of 1.0 x 10(17) and 4.0 x 10(17) cm(-2). An amorphous Fe-Si layer embedded in an amorphous Si was formed in the low-fluence sample, whereas an amorphous Fe-Si surface layer on an amorphous Si was obtained in the high-fluence one. The amorphous Fe-Si layers were crystallized to beta-FeSi(2) after thermal annealing at 800 degrees C for 2 h. Cross-sectional and plan-view TEM observations revealed that, prior to the formation of beta-FeSi(2), the amorphous Fe-Si layers crystallized to alpha-FeSi(2) in the low-fluence sample and to epsilon-FeSi in the high-fluence one. The absence of metastable gamma-FeSi(2) which is considered as a precursor of epitaxially grown beta-FeSi(2) on Si was attributed to the instability of gamma-phase in an amorphous matrix.
采用透射电子显微镜（TEM）研究了非晶态 Fe-Si 层中β-FeSi（2）的形成过程。Si（111）衬底在-150°C下用 120keV Fe 离子照射，剂量分别为 1.0×10（17）和 4.0×10（17）cm（-2）。在低剂量样品中形成了嵌入非晶硅中的非晶态 Fe-Si 层，而在高剂量样品中则得到了非晶硅上的非晶态 Fe-Si 表面层。非晶态 Fe-Si 层在 800°C 下退火 2h 后结晶为β-FeSi（2）。横截面和平面 TEM 观察表明，在形成β-FeSi（2）之前，低剂量样品中非晶态 Fe-Si 层先结晶为α-FeSi（2），而高剂量样品中结晶为ε-FeSi。非晶态基质中γ相的不稳定性导致没有被认为是 Si 上外延生长β-FeSi（2）的前驱体的亚稳γ-FeSi（2）。
