最近实验表明纳米尺度MOSFET中的过剩噪声主要为散粒噪声,而此前研究认为MOSFET中不存在散粒噪声,短沟道MOSFET中的过剩噪声为热噪声.本文基于器件电流模型分析散粒噪声取代热噪声成为过剩噪声主要成分的转变条件,根据该条件对纳米尺度MOSFET噪声特性的预测与文献报道的实验现象、模拟结果以及介观散粒噪声相关结论相符合. Recent experiments show that the excess noise in nano-scale MOSFET is mainly shot noise, but previous studies have found that there is no shot noise in MOSFET and the excess noise in short-channel MOSFET is thermal noise.This paper replaces shot noise with device current model The thermal noise becomes the transition condition of the main components of excess noise. According to this condition, the prediction of the noise characteristics of nanoscale MOSFETs is consistent with the experimental phenomena reported in the literature, the simulation results and the related conclusions of mesoscopic shot noise.