In this paper, we propose a simulation methodology for robust and accurate ab-initio quantum transport simulation down to 3 K of an n-type Si nanowire. This is important to understand the subthreshold swing (SS) at cryogenic temperature. We show that for L_G = 10 nm, the SS is fully dominated by direct tunneling at cryogenic temperature, which is the first time to be demonstrated using ab-initio simulation, to the best of our knowledge. We propose a method to achieve more than 2x speed up in the simulation time and achieve convergence at high gate biases. It is also shown that from the leakage perspective, there is no advantage in operating L_G = 10 nm transistor below 77 K.

在本文中，我们提出了一种模拟方法，用于对低至 3 K 的n型 Si 纳米线进行稳健且准确的从头算量子传输模拟。这对于了解低温下的亚阈值摆动 (SS) 很重要。我们表明，对于 L _G  = 10 nm，SS 完全由低温下的直接隧穿控制，据我们所知，这是第一次使用从头算模拟证明。我们提出了一种方法，可以在仿真时间上实现 2 倍以上的加速，并在高栅极偏置下实现收敛。还表明，从泄漏的角度来看，在 77 K 以下运行 L _G  = 10 nm 晶体管没有优势。