We consider the large-signal equivalent circuit of a field-effect transistor (FET) with characteristics and parameters calculated using a two-dimensional (2D) quasi-hydrodynamic model while taking into account the electron velocity overshoot. In accordance with this equivalent circuit when applied to an AlGaN/GaN high-electron-mobility transistor (HEMT), the avalanche current (in the feedback branch) is zero at all operating points. However, this contradicts the significant difference seen between the results of time-domain simulations of a radiofrequency (RF) amplifier in which the transistor is simulated using a 2D model that does versus does not include the avalanche multiplication of the charge carriers. We propose a new model for the avalanche current generation, based on such simulations including the avalanche multiplication and on the theory of impact-ionization avalanche transit-time (IMPATT) diodes. This model allows the synthesis of amplifiers with high power-added efficiency (PAE).

中文翻译：

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GaN HEMT等效电路中雪崩电流产生的新模型

我们考虑了场效应晶体管（FET）的大信号等效电路，该电路的特征和参数是使用二维（2D）准流体力学模型计算的，同时考虑了电子速度过冲。根据此等效电路，当应用于AlGaN / GaN高电子迁移率晶体管（HEMT）时，雪崩电流（在反馈支路中）在所有工作点均为零。但是，这与在射频（RF）放大器的时域仿真结果之间看到的显着差异相矛盾，在该仿真中，使用2D模型对晶体管进行了仿真，该模型不包含电荷载流子的雪崩倍增。我们为当前的雪崩提出了一种新模型，基于包括雪崩倍增的模拟以及基于碰撞电离雪崩渡越时间（IMPATT）二极管的理论。该模型可以合成具有高功率附加效率（PAE）的放大器。