Hydrodynamic determination of the intrinsic small-signal equivalent circuit of HEMTs

We propose an hydrodynamic approach for the calculation of the small-signal equivalent elements of InGaAs HEMTs. The values of the different elements are calculated from the Y parameters of the intrinsic HEMT and are obtained from the Fourier analysis of the device transient response to voltage-step perturbations at the drain and gate electrodes. For low biases and for frequencies up to 100 GHz, the values of the intrinsic elements are independent of the frequency in the whole range of device operation. However, for frequencies higher than 100 GHz, the transconductance, the conductance and the gate-drain capacity depend on frequency due to the presence of non-stationary dynamic phenomena in the HEMT channel.