原位XPS分析Al2O3作为势垒层的Er2O3/Si结构

在超高真空条件下,通过脉冲激光沉积(PLD)技术制作了Er2O3/Al2O3/Si多层薄膜结构,原位条件下利用X射线光电子能谱(XPS)研究了Al2O3作为势垒层的Er2O3与Si界面的电子结构.XPS结果表明,Al2O3中Al的2p芯能级峰在低、高温退火前后没有变化;Er的4d芯能级峰来自于硅酸铒中的铒,并非全是本征氧化铒薄膜中的铒;衬底硅的芯能级峰在沉积Al2O 3时没有变化,说明Al2O3薄膜从沉积到退火不参与任何反应,与Si界面很稳定;在沉积Er2O3薄膜和退火过程中,有硅化物生成,表明Er2O3与Si的界面不太稳定,但随着Al2O3薄膜厚度的增加,其硅化物中硅的峰强减弱,含量减少,说明势垒层很好地起到了阻挡扩散的作用.

In-Situ Analysis of the Er2O3/Si Structure Using Al2O3 as Barrier Layer by X-Ray Photoelectron Spectroscopy

The multi-layer films with Er2 O3/Al2 O3/Si structure were fabricated in the super-high vacuum by the pulsed laser deposition (PLD) technique.With the in-situ condition,the electronic structure of the interface between Si substrate and Er2O3 layer with Al2O3 barrier Layer was studied by the X-ray photoelectron spectroscopy (XPS).The XPS experimental result shows that the Al 2p core level peaks in Al2O3 layer have no changes before and after low and high temperature annealing process.The Er 4d core level peaks come from the erbium in erbium silicide,rather than that in the intrinsic erbium oxide film.There is no change in the core level peak of the substrate silicon when the Al2O3 is deposited.The results indicate that Al2O3 films don't participate in any reaction from deposition to annealing process and the interface between Al2O3 layer and Si is stable.The silicide is formed during the deposition of Er2O3 thin films and annealing process,indicating that the interface between Si substrate and Er2O3 is not stable.But the intensity and content of Si peaks in the silicide decrease with the increase of the thick-ness of the Al2O3 films.The results indicate that the barrier layer plays an important role in preventing the diffusion.