Extraction method for parasitic capacitances and inductances of HEMT models

- A new extraction method for extrinsic parameters of HEMT model is proposed.
- The capacitances and inductances can be obtained simultaneously.
- The proposed method is compared with the conventional method.
- The values obtained by method can be used to establish the small-signal model of HEMT.
- The model can accurately reproduce the small-signal characteristic of the HEMT.

A new method to extract parasitic capacitances and inductances for high electron-mobility transistors (HEMTs) is proposed in this paper. Compared with the conventional extraction method, the depletion layer is modeled as a physically significant capacitance model and the extrinsic values obtained are much closer to the actual results. In order to simulate the high frequency behaviour with higher precision, series parasitic inductances are introduced into the cold pinch-off model which is used to extract capacitances at low frequency and the reactive elements can be determined simultaneously over the measured frequency range. The values obtained by this method can be used to establish a 16-elements small-signal equivalent circuit model under different bias conditions. The results show good agreements between the simulated and measured scattering parameters up to 30 GHz.