Suppression of random dopant-induced threshold voltage fluctuations in sub-0.1-μm MOSFET's with epitaxial and δ-doped channels
Suppression of random dopant-induced threshold voltage fluctuations in sub-0.1-μm MOSFET's with epitaxial and δ-doped channels
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DOI：
10.1109/16.777162
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发表时间：
1999-08-01
影响因子：
3.1
通讯作者：
Saini, S
中科院分区：
文献类型：
--
作者：
Asenov, A;Saini, S
详细的三维（3-D）统计“原子”模拟研究了具有外延沟道和δ掺杂的抗波动的0.1 μ m以下MOSFET结构。通过对大量具有均匀掺杂通道的传统器件的原子模拟结果的总结，强调了提高sub-0.1 μ m一代晶体管的抗涨落能力的必要性。根据我们的原子结果，常规器件中随机掺杂诱导的阈值电压波动的掺杂浓度依赖性比解析预测的四根依赖性强。因此，这种器件的缩放m将受到“固有的”随机掺杂引起的波动的限制，比预期的要早。我们的原子模拟证实，在MOSFET的沟道中引入薄外延层可以有效地抑制0.1 μ m以下器件中随机掺杂引起的阈值电压波动。我们首次观察到，随着外延通道后掺杂浓度的增加，阈值电压波动出现了“异常”的降低，这可能归因于筛选效应。此外，我们首次研究了位于外延层后面的δ掺杂对本征阈值电压波动的影响。在一定外延层厚度以上，我们观察到随着δ掺杂量的增加，阈值电压波动明显异常降低，这一现象也与筛选有关，增强了δ掺杂在设计适当比例抗波动的0.1 μ m以下MOSFET中的重要性。
A detailed three-dimensional (3-D) statistical "atomistic" simulation study of fluctuation-resistant sub-0.1-mu m MOSFET architectures with epitaxial channels and delta doping is presented. The need for enhancing the fluctuation resistance of the sub-0.1-mu m generation transistors is highlighted by presenting summarized results from atomistic simulations of a wide range of conventional devices with uniformly doped channel. According to our atomistic results, the doping concentration dependence of the random dopant-induced threshold voltage fluctuations in conventional devices is stronger than the analytically predicted fourth-root dependence. As a result of this, the scaling of such devices M-ill be restricted by the "intrinsic" random dopant-induced fluctuations earlier than anticipated. Our atomistic simulations confirm that the introduction of a thin epitaxial layer in the MOSFET's channel can efficiently suppress the random dopant-induced threshold voltage fluctuations in sub-0.1-mu m devices. For the first time, we observe an "anomalous" reduction in the threshold voltage fluctuations with an increase in the doping concentration behind the epitaxial channel, which rye attribute to screening effects. Also, for the first time we study the effect of a delta-doping, positioned behind the epitaxial layer, on the intrinsic threshold voltage fluctuations. Above a certain thickness of epitaxial layer, we observe a pronounced anomalous decrease in the threshold voltage fluctuation with the increase of the delta doping, This phenomenon which is also associated with screening, enhances the importance of the delta doping in the design of properly scaled fluctuation-resistant sub-0.1-mu m MOSFET's.