Quantitative Characterization of Plasma-Induced Defect Generation Process in Exposed Thin Si Surface Layers
Quantitative Characterization of Plasma-Induced Defect Generation Process in Exposed Thin Si Surface Layers
复制标题
暴露的薄硅表面层中等离子体诱发缺陷产生过程的定量表征
DOI：
10.1143/jjap.47.2446
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发表时间：
2007
影响因子：
1.5
通讯作者：
K. Ono
中科院分区：
文献类型：
--
作者：
K. Eriguchi;A. Ohno;D. Hamada;M. Kamei;H. Fukumoto;K. Ono
利用椭圆偏振光谱（SE）和光反射光谱（PR）研究了等离子体辐照下硅表面层中缺陷的产生过程。采用两种等离子体源与Ar-气体混合物;一个是DC等离子体和其他，电子回旋共振（ECR）等离子体。在Ar-DC等离子体暴露与300 V偏压的情况下，SE分析与优化的光学模型确定1 nm厚的界面层（IL）之间的表面层和衬底，而在ECR的情况下，约0.5 nm厚的界面层被确定。这种差异归因于两个等离子体源之间的自偏置电压（Vdc）。为了量化的损害，我们已经修改了PR分析技术，以评估等离子体诱导的载流子陷阱的网站密度，通过相关的Si表面电位的变化被困载流子密度。结合等离子体诊断的结果，我们发现，计算的缺陷产生的概率由撞击离子的数量级为10-2和10-5，在目前的直流和ECR等离子体条件下，分别，和概率依赖于Vdc。所获得的结果使我们能够预测等离子体引起的物理损伤的设备提前在等离子体工艺设计阶段。
The defect generation process in Si surface layer induced by plasma exposures is studied by two optical analyses, spectroscopic ellipsometry (SE) and photoreflectance spectroscopy (PR). Two plasma sources with Ar-gas mixtures are employed; one is DC plasma and the other, electron cyclotron resonance (ECR) plasma. In the case of Ar-DC plasma exposure with 300 V bias, the SE analysis with an optimized optical model determines 1-nm-thick interfacial layer (IL) between the surface layer and the substrate, while in the case of the ECR, approximately 0.5-nm-thick interfacial layer is identified. This difference is attributed to that in self-bias voltages (Vdc) between two plasma sources. In order to quantify the damage, we have modified the PR analysis technique in order to evaluate the plasma-induced carrier trap site density, by correlating the Si surface potential change to the trapped carrier density. Combined with the results by plasma diagnostics, we found that the calculated defect generation probabilities by an impinging ion were the orders of 10-2 and 10-5 in the present DC and ECR plasma conditions, respectively, and that the probability depends on the Vdc. The obtained results enable us to predict the plasma-induced physical damage to the devices in advance at the stage of plasma process designs.