An Accurate and Full-Range Analytical Current Model for Nanowire Heterojunction TFET

In this article, we present a compact analytical model for the drain current of the nanowire heterojunction tunneling field-effect transistor (FET). The model is developed by leveraging the surface potential solution and Kane’s equation, and it incorporates the ambipolar behavior of the device. Notably, in addition to considering source/drain depletions, our model effectively captures the influence of mobile charge in both inversion and accumulation states using a simplified thermal injection method. To assess the model’s accuracy, we validate it against TCAD simulations. The results demonstrate that the model successfully predicts the dependencies of the surface potential and drain current on biases, doping concentration, and channel length across the entire operation range. Furthermore, for the verified GaAs $_{\text{0.5}}$ Sb $_{\text{0.5}}$ /In $_{\text{0.53}}$ Ga $_{\text{0.47}}$ As material system, the results reveal that the screening effect caused by holes is more pronounced compared to that induced by electron, and a detailed examination of the underlying reasons behind this observation is provided.