Effect of deposition parameters on the stress gradient of CVD and PECVD poly-SiGe for MEMS applications
Effect of deposition parameters on the stress gradient of CVD and PECVD poly-SiGe for MEMS applications
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沉积参数对 MEMS 应用中 CVD 和 PECVD 多晶 SiGe 应力梯度的影响
DOI：
10.1117/12.524406
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
A. Witvrouw
中科院分区：
文献类型：
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作者：
T. Van der Donck;J. Proost;C. Rusu;K. Baert;C. van Hoof;J. Celis;A. Witvrouw
研究了沉积参数和Ge含量对多晶SiGe薄膜应力梯度的影响。薄膜的厚度范围为1.2 - 2.3 μm，分别在450 °C和520 °C下通过化学气相沉积（CVD）和等离子体增强化学气相沉积（PECVD）沉积。Ge含量在45at%和64at%之间变化。X射线衍射分析表明，PECVD和CVD薄膜均为多晶。通过测量1 mm长的释放杠杆的偏转来确定应力梯度。发现应力梯度随着Ge含量的增加而减小。用极低功率的SF6/O2等离子体减薄具有55at% Ge的CVD膜。测量应力梯度作为膜厚度的函数。通过将计算的剖面的弯矩与从测量的应力梯度获得的弯矩相匹配来计算应力剖面。最大的应力变化正好发生在薄膜/衬底界面处。发现PECVD膜与具有类似厚度的CVD膜相比具有较低的应力梯度。这是由TEM微观结构的差异解释的：CVD膜具有更多的V形晶粒，而PECVD膜具有更多的柱状晶粒。
The effect of the deposition parameters and Ge content on the stress gradient in poly-SiGe films was investigated. The films, ranging in thickness from 1.2 to 2.3 μm, were deposited by chemical vapor deposition (CVD) at 450 °C and plasma enhanced chemical vapor deposition (PECVD) at 520 °C. The Ge content was varied between 45 and 64 at%. Xray diffraction revealed that both PECVD and CVD films were polycrystalline. The stress gradient was determined by measuring the deflection of 1 mm long released cantilevers. The stress gradient was found to decrease with increasing Ge content. A CVD film with 55 at% Ge was thinned using a very low power SF6/O2 plasma. The stress gradient was measured as a function of film thickness. The stress profile was calculated by matching the bending moment of the calculated profile to the bending moment obtained from the measured stress gradient. The largest change in stress occurs right at the thin film/substrate interface. PECVD films were found to possess a lower stress gradient compared to CVD films with similar thickness. This was explained by differences in TEM microstructure: CVD films have more Vshaped grains, while PECVD films have more columnar grains.