Scalable Large-Signal Modeling for GaN HEMTs Including Kink Effect

An improved scalable large-signal model for gallium nitride high-electron-mobility transistors (GaN HEMTs) based on the EEHEMT model is proposed. The derived DC model can accurately predict the current-voltage behavior including the kink effect over a wide range of bias points by introducing the parameter <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$V_{\textrm {kink}}$ </tex-math></inline-formula> and new equations using fitting parameters. To ensure the scalability of the model, the scaling rules are modified. The proposed model has been validated by comparing the measured and modeled DC I–V characteristics and multibias scattering parameters (S-parameters) up to 40 GHz for GaN HEMTs with different gate widths including <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2\times 25~\mu $ </tex-math></inline-formula>m, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2\times 50~\mu $ </tex-math></inline-formula>m, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2\times 75~\mu $ </tex-math></inline-formula>m, and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2\times 100~\mu $ </tex-math></inline-formula>m gate width (number of gate fingers <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times $ </tex-math></inline-formula> unit gate width).