Influence of Fin-Like Configuration on Small-Signal Performance of AlGaN/GaN HEMTs

In this work, a new small-signal model (SSM), which is called the distributes intrinsic subdevice model (DISDM), is established for AlGaN/gallium nitride (GaN) Fin-like high-electron mobility transistors (HEMTs) according to the device structure feature. Perfect agreements between the measured and simulated scattering parameters (S-parameters) illustrated the validity of the DISDM and the accuracy of parameters extracted from the new model. Then, the characteristics of Fin-like HEMTs are analyzed using the DISDM theoretically. Different from the traditional model, the DISDM can accurately show the characteristics of the Fin-like HEMTs, especially the “double-peak” of the intrinsic transconductance. Compared with the planar HEMTs, the Fin-like HEMTs exhibit a higher linearity in direct current and small-signal parameters. For Fin-like HEMTs with different recess depths and duty ratios, the variation of the small-signal parameters and the linearity of devices were characterized to evaluate the performance of devices and optimize the process in the end.