光學曲率量測鈦之吸氧能力與氮化鈦之應力疏散

Measurement of Ti ability to absorbing oxygen and TiN stress relaxation by substrate curvature

程書彥(Cho-Jen Tsai)

指導教授 ： 蔡哲正

國立清華大學/工學院/材料科學工程學系/碩士(2006年)

摘要

摘要
利用In-Situ curvature measurement量測Ti薄膜的吸氧能力與TiN薄膜的應力疏散是本實驗的主要目的。除了曲率量測之外，還配合XRD峰值變化、Auger電子分析儀的成分分析與TEM的微結構分析，來釐清造成試片曲率變化的各種可能性。
Ti/SiO2/Si結構在退火爐內持溫會發現氧的擴散造成Ti薄膜受到壓應力，相對應也會造成XRD峰值偏移。如此一來氧在Ti的濃度可以由曲率或者峰值偏移來定量。再配合擴散理論，可以由電腦Fitting出氧在Ti中的擴散係數與擴散活化能。
但是在電腦Fitting過程中會發現額外的壓應力(即不是由擴散方程式解得的多餘項)產生，這是因為在Ti/SiO2介面可能會生成新的相，或者是介面的氧擴散進入Ti所造成。(可以由Auger電子分析儀的結果或TiN/Ti/SiO2/Si的XRD與TEM的結果推測得到。)
TiN的應力疏散可能會因為Texture不同而起始溫度不同，如TiN/Si結構在600oC開始應力疏散，而TiN/Ti/SiO2/Si結構則在400oC就開始疏散。這兩種結構最大的區別就在於TiN texture不同(XRD結果顯示)。而應力疏散機制從XRD峰值增強、TEM Bright Field 與Dark Field分析則可推測極有可能是晶粒成長所造成。

關鍵字

鈦 ； 氧

並列摘要

Abstract

Ti/SiO2/Si, TiN/Si and TiN/Ti/SiO2/Si structures were annealed in vacuum to observe the ability of Ti absorbing oxygen and the stress relaxation of TiN layer. The stress of the film was determined in situ by measuring the curvature of the sample during the annealing process. The phases and the microstructure of the film after annealing process were identified using XRD, AES, and TEM. A clear correlation was between the evolution of stress and the absorption of oxygen atoms by the Ti film.

From the XRD data, we can find that the (002) peak of Ti shifts to low angle at 280oC~400oC in the Ti/SiO2/Si system. It is due to the oxygen-induced Ti lattice expansion. The content of oxygen increases as the annealing temperatures and time increase, and this process let the stress become more compressive. The experiment finds that the content of oxygen can be monitored by in-situ curvature measurement. Moreover, diffusivity and the activation energy of oxygen in Ti film can be extracted.

The stress relaxation of TiN is due to grain growth proved by Dark Field TEM and XRD intensity. The starting temperatures for the stress relaxation are different between TiN/Si and TiN/Ti/SiO2 system because of different TiN textures in these two systems.

並列關鍵字

Ti ； O

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