本論文主要探討應力對於MOS結構中二氧化鉿薄膜特性的影響。從實驗成果觀察到應力的施加造成二氧化鉿薄膜結晶特性提升，並衍生出其影響與覆蓋層的形成有關，因此在論文後半段探討覆蓋層對於二氧化鉿薄膜結晶性的探討。
由實驗結果得知，壓應力與張應力對於二氧化鉿薄膜有相似的作用，此應力的效果為抑制二氧化鉿與矽基板中的介面層成長，並且伴隨著減緩介面層成長所可能造成的矽向外擴散。我們猜測其原因與應力加強退火過程中原子的重新排列有關係，導致形成較低氧空缺濃度的二氧化鉿薄膜，而此二氧化鉿薄膜有效抑制氧氣擴散，進而減緩介面層成長和矽向外擴散。
此外，本論文證明二氧化鉿的結晶特性與外加應力的關聯性，連結於矽向外擴散所形成二氧化矽的覆蓋層。二氧化鉿與矽基板中間的介面層在退火過程中增厚，由此介面層將發射矽原子至二氧化鉿薄膜表面，而形成二氧化矽覆蓋層而此自發性形成的二氧化矽的覆蓋層會抑制二氧化鉿的結晶性。

In this thesis, the stress effect of HfO2 insulating layer within the MOS structure has been discussed. From the experiment result, we can see that the crystallization of HfO2 was enhanced by constrained annealing, which inhibited the formation of capping layer on HfO2. Therefore, the further discussion of capping layer on HfO2 would be discussed in details in the second part of this thesis.
The experiment has shown that the compressive and tensile stresses have the similar effect to HfO2. The constraint stress inhibited further growth of the interfacial layer (IL) between HfO2 and Si, suppressing the IL-growth-induced Si outward emission. This fact was associated with atomic rearrangement that was induced during constrained annealing, resulting in the formation of a robust HfO2 layer with low oxygen vacancy. Such an HfO2 layer effectively suppressed the inward diffusion of oxygen, the IL growth and the Si out-diffusion.
In addition, we can see evidence of the relationship of crystallization and the forms of SiO2 capping layer when HfO2 is mechanically constrained. During annealing, the growth of interfacial layer in Si/HfO2 led to an out-emission of Si from interface to film surface and self-formed a SiO2 capping layer. The crystallization of HfO2 film on Si substrate was suppressed due to the self-capping effect.

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