Nonlinear Dispersive Modeling of Electron Devices Oriented to GaN Power Amplifier Design

Abstract

This paper presents a new modeling approach accounting for the nonlinear description of low-frequency dispersive effects (due to thermal phenomena and traps) affecting electron devices. The theoretical formulation is quite general and includes as particular cases different models proposed in the literature. A large set of experimental results, oriented to microwave GaN power amplifier design, is provided to give an exhaustive validation under realistic device operation

Analysis of the gate current as a suitable indicator for FET degradation under nonlinear dynamic regime

“…11 the static drain current characteristics at constant gate voltage for the fresh device and for the devices after the 24-h stresses. It is evident that, in both cases, an important current collapse [11] occurs which can be related to trap creation induced by the forced stress conditions [12]. As a matter of fact, also in the present case, the average value of the gate current appears a valuable indicator for quantifying device degradation under dynamic operation, that is: increasing values (in magnitude) of the average gate current unquestionably correspond to more severe device performance drop.…”

Nonlinear modeling of LDMOS transistors for high‐power FM transmitters

“…According to [18], dynamic I/V characteristics can be obtained starting from the DC ones, by using proper algebraic functions. According to previous results, in the present case, just thermal effects due to device self-heating have to be taken into account; thus, the following simple formulation can be considered:…”

Identification technique of FET model based on vector nonlinear measurements

“…Load-pull experiments were performed at a fixed bias point, V GS0 ¼ 22 V and V DS0 ¼ 20 V (class-A operation), and at two different frequencies, 2 MHz and 4 GHz. The low frequency value is properly chosen above the cutoff frequency of the LF dispersion, as experimentally investigated in [4]. Such an approximation, which is valid for the considered case, has to be verified depending on the device under test.…”

“…Nevertheless this approach, which is accurate for the determination of the parasitic elements and the nonlinear charge sources, yields inaccurate results when low-frequency (LF) dispersion is significant [3]. LF dispersion, which is originated by the presence of defects in the materials and thermal effects, mainly affects the nonlinear behaviour of the drain-source current generator [4]. To properly account for LF dispersion, either pulsed I-V measurements or low-frequency vector nonlinear measurements [4] constitute valid techniques to characterise and model the nonlinear current source.…”

“…LF dispersion, which is originated by the presence of defects in the materials and thermal effects, mainly affects the nonlinear behaviour of the drain-source current generator [4]. To properly account for LF dispersion, either pulsed I-V measurements or low-frequency vector nonlinear measurements [4] constitute valid techniques to characterise and model the nonlinear current source. In [5,6], highfrequency nonlinear measurements are exploited to identify both the I-V and Q-V nonlinear functions.…”