According to quantum transport simulations, source-to-drain tunneling (SDT) has been recognized as the main cause leading to subthreshold swing (SS) saturation and degradation of short-channel MOSFETs at cryogenic temperatures. Generally, at a given low temperature, the steeper constant SS of thermionic currents may be overwhelmed by less-steep SDT currents at lower gate bias, degrading the average SS. Our simulations show that the SS of SDT currents is insensitive to temperatures for a MOSFET with a given channel length, accounting for SS saturation as lowering temperature. This work reveals the key points differentiating the possible reasons (interface traps, band tail and SDT) of SS saturation at cryogenic temperatures. We also study the impacts of carrier effective masses, gate-SD underlapping and a tunneling barrier at the source junction on SS saturation. SDT may pose a potential challenge and limit for scaling cryogenic CMOS of a quantum processor.

中文翻译：

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由于低温下的源漏隧道导致纳米级 MOSFET 的亚阈值摆动饱和

根据量子传输模拟，源漏隧穿（SDT）已被认为是导致亚阈值摆动的主要原因。SS) 低温下短沟道 MOSFET 的饱和和退化。通常，在给定的低温下，陡峭的常数SS 的热离子电流可能会被较低栅极偏压下较不陡峭的 SDT 电流所淹没，从而降低平均值 SS. 我们的模拟表明，SS 的 SDT 电流对具有给定沟道长度的 MOSFET 的温度不敏感，占 SS随着温度的降低而饱和。这项工作揭示了区分可能的原因（界面陷阱、带尾和 SDT）的关键点。SS在低温下饱和。我们还研究了载流子有效质量、栅极 SD 重叠和源结处的隧道势垒对SS饱和。SDT 可能对扩展量子处理器的低温 CMOS 构成潜在挑战和限制。