An Analytical Surface-Potential-Based I-V and C-V Models of AlGaN/GaN HEMTs

This paper proposes a surface-potential based I-V model of AlGaN/GaN high electron mobility transistors (HEMTs). The two lowest subbands E0 and E1 in the triangular electron potential well are incorporated into the model, and the macro-micro variable superposition (MMVS) method is proposed to calculate the surface potential. MMVS method avoids the need to use a smooth function after partition calculations in the compact modeling and has an important improvement on calculation efficiency in the case of remaining the enough calculation accuracy. The MMVS method overcomes the bottleneck of the compromise between accuracy and efficiency of the previous methods. Based on the MMVS method, we derive an analytical solution of the surface potential for AlGaN/GaN HEMTs and compared the analytical solution with the numerical results in the whole forward working area. Furthermore, we establish and analyze the I-V and C-V models and also verify the accuracy and applicability of these models. In addition, the self-heating effect is taken into account in the current-voltage characteristics of AlGaN/GaN HEMTs, which can effectively reflect the phenomenon that the device output characteristics change as the temperature increases. As a result, this model provides not only a valuable tool for the design and optimization of AlGaN/GaN HEMTs’ devices and circuits but also a new research method of compact modelling for semiconductor devices.