磁控溅射法制备β型Fe_3Si_8M系三元薄膜

β-Fe_3Si_8M ternary alloy thin films prepared by magnetron sputtering

二元β-FeSi2是一种非常有潜力的环境友好型半导体,但由于是线性化合物,所以很难制备较高质量的β单相.本文从β-FeSi2相的基本团簇出发,利用"团簇+连接原子"结构模型,设计制备了Fe3Si8M(M=B,Cr,Ni,Co)系三元薄膜.研究了Fe3Si8M系三元薄膜的结构、成分和光电特性.结果表明,溅射态薄膜都为非晶态,经850C/4h退火后可全部转换为晶态,引入的第三组元M不同会影响退火后的相转变和结晶质量,Cr和B为第三组元时可实现单一β相,Co作为第三组元时,薄膜以α相为主表现为金属特性.B,Cr和Ni作为第三组元的样品中半导体性质都有不同程度的体现,但相比较而言,Fe2.7Si8.4B0.9薄膜的半导体性能最为明显,其电阻率为0.17·cm、载流子浓度为2.8×1020cm3、迁移率为0.13cm2/V·s,带隙宽度约为0.65eV.所以引入合适的第三组元可以扩展β相相区,并实现晶态三元β型硅化物薄膜与二元β-FeSi2薄膜的半导体性能相近.

β-FeSi2 is a promising environment-friendly semiconductor material. However it is difficult to obtain pure phase tbr such a line compound. To investigate the solubilities for a third alloying elements, in this work Fe3Si8M （M = B, Cr, Ni, Co） ternary alloys are designed based on the cluster-plus-glue-atom-modek Thin films are then prepared using magnetron sputtering. The as-deposited films are all amorphous and become crystallized after annealing at 850° for 4 h. It is shown that samples alloyed with third components Cr and B can reach single β phase easily. However, the main phase is a phase and the fihns tend to exhibit metallic characteristics while alloyed with Co. Of these films, the Fe2.7Si8.4B0.9 film presents the most prominent semiconductor performance, and it has a resistivity of 0.17 Ω.cm, a sheet carrier concentration of 2.8 × 10^20 cm -3, a mobility of 0.13 cm2/V.s and a band-gap width of 0.65 eV. It is confirmed that doping a proper third component can expand the 13 phase zone, exhibiting a similar semiconductor property to that of binary β-FeSi2.