Large-Signal FET Modeling based on Pulsed Measurements

Abstract

The new FET model presented in this paper highlights a method through which complex current flow dynamics, arising from typical dispersion phenomena, can be modeled in equivalent circuits. Static and bias-dependant dynamic/pulsed currents are characterized using a new single mathematical expression and subsequently implemented into a large-signal circuit topology as a single current source. The model is based on a well-established conventional DC model and only minimal alteration is required. In this work we extend the range of validity to full large-signal operation including accurate prediction of nonlinear harmonic distortion and inter-modulation distortion (IMD) products. Furthermore, the single current source approach enhances the overall equivalent circuit topology's consistency with the physical device, a particularly favorable feature in such device models.

An improved empirical large-signal model for the GaAs- and GaN-based HEMTs

“…To characterize the frequency dispersion due to the deep‐level charge‐trapping effects found in most GaAs/GaN HEMTs, a similar back‐gating method [14–16] based on the multi‐bias Pulsed I–V measurements with four‐terminal circuit topology introduced in [16] has been employed. Since the charge‐trapping effects in HEMTs are observable by comparing the Pulsed I–V characteristics at different quiescent biasing points, the correction of the model parameters that accounts for the surface and substrate trapping effects can be determined from a set of Pulsed I–V measurements [4], as given below: where P 1′cvgsq , P 1′cvdsq , Ipk ′cvgsq , Ipk ′cvdsq , V pk′cvgsq , V pk′cvdsq , and α ′cvdsq are the quiescent‐bias dependent fitting parameters.…”

Equivalent circuit GaN HEMT model accounting for gate-lag and drain-lag transient effects

“…In this model we propose the addition of passive filter networks at the gate and at the drain. It has been proven in our previous work that this method can account for g m and g ds dispersion in HEMTs [5], and here we apply it to a GaN device.…”