The Band Model and the Etching Mechanism of Silicon in Aqueous KOH
The Band Model and the Etching Mechanism of Silicon in Aqueous KOH
复制标题
硅在KOH水溶液中的能带模型及刻蚀机理
DOI：
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发表时间：
1995
期刊：
影响因子：
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通讯作者：
C. Wan
中科院分区：
文献类型：
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作者：
L. Chen;Minjan Chen;C. Lien;C. Wan
通过测得的开路电位和平带电压构建了 2M KOH 水溶液中 n-Si 的能带图。提出了一种光电流敏感性方法来确定平带电压。通过这种新方法测定了 2M KOH 中 n-Si 的平带电压为 -1.04 V/SCE（饱和甘汞电极）。还构建了同一电解质中p-Si的能带图。通过能带图预测了 n-Si/KOH 界面处载流子的积累，并通过类似欧姆接触的 I-V 曲线进行了确认。 p-Si/KOH 界面处载流子的耗尽可以通过能带图预测，并通过整流 I-V 特性得到证实。 Si在阳极偏压下的钝化归因于氧化膜的形成。氧化速率和氧化产物扩散速率之间的竞争决定了阳极氧化是蚀刻还是钝化过程。假设蚀刻氧化主要由电化学反应决定。这些参与电化学反应的载流子的传输可以通过能带图来解释。所有蚀刻或钝化现象都与能带图观点的预测一致。重掺杂硅的刻蚀停止归因于高载流子浓度下氧化膜生长速率的提高
The energy band diagram of n-Si in aqueous 2M KOH is constructed by the measured open-circuit potential and the flatband voltage. A photocurrent susceptivity method was proposed to determine the flatband voltage. A flatband voltage of -1.04 V/SCE (saturated calomel electrode) for the n-Si in 2M KOH was determined by this new method. The energy band diagram of the p-Si in the same electrolyte is also constructed. Accumulation of carriers at the n-Si/KOH interface is predicted by the band diagram and confirmed by the ohmic-contact-like I-V curve. Depletion of carriers at p-Si/KOH interface is predicted by the band diagram and confirmed by the rectifying I-V characteristics. The passivation of Si under anodic bias is attributed to the formation of an oxide film. The competition between the oxidation rate and the diffusion rate of oxidation product determines whether the anodic oxidation is an etching or passivation process. The etching oxidation is assumed to be dominated by the electrochemical reaction. The transport of these carriers which participate in the electrochemical reaction can be explained by the energy band diagram. All etching or passivation phenomena are consistent with the prediction from the band diagram viewpoint. The etch stop for heavily doped Si is attributed to the enhanced growth rate of oxide film under high carrier concentration