Body self bias in fully depleted and non-fully depleted SOI devices
Body self bias in fully depleted and non-fully depleted SOI devices
复制标题
完全耗尽型和非完全耗尽型 SOI 器件中的体自偏置
DOI：
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发表时间：
1994
期刊：
影响因子：
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通讯作者：
P. Ko
中科院分区：
文献类型：
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作者：
K. Hui;M. Chan;F. Assaderaghi;C. Hu;P. Ko
SOI工艺的一个主要优点是易于器件隔离。通过使用梅萨蚀刻或场氧化，可以选择性地去除硅膜，从而使SOI器件的主体彼此电隔离。每个机构可以单独偏置，或者在大多数情况下，保持浮动。然而，存在与浮体相关联的异常，即阈值电压漂移、电流特性中的扭结以及饱和区中的输出电阻的退化。出现这种异常是因为浮体电位随外部偏置而变化，这又改变了阈值电压。身体电位转移的量也取决于技术和材料质量。为了消除这些异常，已经提出了不同的方案来偏置身体。这些方案增加了工艺复杂性并增加了器件面积。同样不清楚的是，这种方案是否能有效地偏置完全耗尽装置的主体，在这种情况下，没有准中性主体。在本文中，我们已经开发了一个模型来预测体电位的完全耗尽（FD）和非完全耗尽（NE）SOI器件。我们发现，与一般的看法相反，扭结异常也发生在FD SOI。然而，扭结效应随着膜厚度的减小而减小。对于薄硅膜SOI器件，浮体长沟道SOI器件的输出电阻可以大于1 M/spl Ω/-/spl μ/m。
One major advantage in SOI processing is the ease of device isolation. By using mesa etching or field oxidation the silicon film can be selectively removed, thereby electrically isolating the bodies of SOI devices from one another. Each body can be individually biased or in most cases, left floating. However there are anomalies associated with a floating body, namely threshold voltage shifting, kink in the current characteristics, and degradation of output resistance in the saturation region. Such anomalies arise because the floating body potential changes with the external biases, which in turn changes the threshold voltage. The amount of body potential shifting is also dependent on the technology and the material qualities. To eliminate these anomalies different schemes have been proposed to bias the body. These schemes add to the process complexity and increase the device area. It is also unclear if such schemes are effective in biasing the body of a fully depleted device, in which case the presence of a quasi-neutral body is lacking. In this paper we have developed a model to predict the body potentials of both Fully Depleted (FD) and Non-Fully Depleted (NE) SOI devices. We found that contrary to general belief the kink anomaly also occurs in FD SOI. However the kink effect diminishes as the film thickness is reduced. For thin silicon film SOI devices, output resistance for floating body long channel SOI devices can be larger than 1 M/spl Omega/-/spl mu/m.