Steep Subthreshold Switching With Nanomechanical FET Relays
Steep Subthreshold Switching With Nanomechanical FET Relays
复制标题
使用纳米机械 FET 继电器进行陡峭亚阈值开关
DOI：
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发表时间：
2015
影响因子：
3.1
通讯作者：
Avik W. Ghosh
中科院分区：
文献类型：
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作者：
D. Unluer;Avik W. Ghosh
我们提出了一个基于悬臂梁的纳米机电场效应管的电子开关物理模型，重点关注其开关曲线的陡峭度。我们发现电压转移特性的亚阈值摆动是由两个独立的考虑因素决定的。当继电器上的几个偶极电荷一起运动并放大主动转矩时，曲线的陡度在玻尔兹曼极限之外得到改善。由于静电不稳定和拉入力的作用，悬臂梁尖端和漏极之间的气隙突然关闭，隧道电流呈指数级增加，陡度也得到了改善。对于小型继电器，偶极和短程范德华粘附力占主导地位，而对于较长的悬臂梁，电容能量起主要作用。单个的拉入和拉出阶段表现出由电容力驱动的非常低的亚阈值摆动，并通过偶极相关进一步增强。然而，当亚稳态和稳态沿着电压扫描的正反相交换时，这种急剧切换是以强滞后为代价的。
We present a physical model for electronic switching in the cantilever-based nanoelectromechanical FETs, focusing on the steepness of its switching curve. We find that the subthreshold swing of the voltage transfer characteristic is governed by two separate considerations. The steepness of the curve is improved beyond the Boltzmann limit when several dipolar charges sitting on the relay move together and amplify the active torque. The steepness is also improved by electrostatic destabilization and pull-in forces that abruptly close the airgap between the tip of the cantilever and the drain, and exponentially enhance the tunnel current. For small sized relays, dipolar and short-range van der Waals sticking forces dominate, while for longer cantilevers the capacitive energy acquires a major role. The individual pull-in and pull-out phases demonstrate a remarkably low subthreshold swing driven by the capacitive forces, sharpened further by dipolar correlation. The sharp switching, however, comes at the expense of a strong hysteresis as the metastable and stable states interchange along the forward and reverse phases of the voltage scan.