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为了提高VLSI多晶硅工艺中所用多晶硅线条的导电率,目前正考虑用硅化物(如WSi_2、MoSi_2和TaSi_2)作为多晶硅线条上的覆盖层。多晶硅/硅化物结构的优点之一,估计可能是,它是一种可氧化的自钝化结构。在某些类似于FET多晶硅工艺所采用的那些氧化条件下,孔隙可能在多晶硅层中扩大,或缺乏结构完整性的不需要的氧化层可能在硅化物表面扩展。本文讨论了这些现象的氧化机理。
In order to increase the conductivity of polycrystalline silicon lines used in the VLSI polysilicon process, silicides such as WSi_2, MoSi_2, and TaSi_2 are currently considered as the capping layers on the polysilicon lines. One of the advantages of a polysilicon / silicide structure, it is estimated, is that it is an oxidizable, self-passivated structure. Under some oxidizing conditions similar to those employed in FET polysilicon processes, voids may expand in the polysilicon layer or unwanted oxide layers that lack structural integrity may expand on the silicide surface. This article discusses the oxidation mechanism of these phenomena.