Comparison of Four De-Embedding Methods With Application to GaN HEMT Devices Characterization

In order to describe the RF behavior of active devices, accurate on-wafer characterization is essential. In this paper, four de-embedding methods are compared and their impacts on a gallium nitride high-electron-mobility transistor (GaN HEMT) are investigated. The S-parameters of the passive test structures are obtained using a 3-D electromagnetic (EM) simulator. On this basis, small-signal equivalent circuit models are established to compare the effects of these four de-embedding methods in the frequency range of 1 to 50 GHz. In addition, the influence on the calculation of the cutoff frequency (Formula presented.) and the maximum oscillation frequency (Formula presented.) is also investigated. Subsequently, corresponding nonlinear models are established. The results indicate that these de-embedding methods affect the model parameters, but their effect on the simulation results of the device models is relatively minor.