The modulation of characteristics in AlGaN/GaN High electron mobility transistors (HEMTs) using multiple field plate technology

Abstract This study utilizes ATLAS-TCAD to investigate and propose a multiple electrode extension AlGaN/GaN HEMT. It explores different electrode extension structures combined with variations in plate dimensions to improve device operating capability and electrical breakdown. The study examines the electrical breakdown behavior, channel electric field distribution, output transfer characteristics, threshold frequency (Ft), and peak oscillation frequency (Fmax) under different electrode extension structures. The research demonstrates that the introduction of electrode extension structures can effectively modulate the distribution of channel electric fields. The electrode extension structure has minimal impact on the device’s transfer characteristics and output current. The dimension of the gate electrode extension significantly affects the reduction of the cutoff frequency, whereas the source electrode extension has almost no impact on the cutoff frequency. The introduction of the electrode extension structure leads to a decrease in the maximum oscillation frequency. As the dimension of the electrode extension increases, the decreasing trend slows down, with the gate electrode extension showing a greater reduction trend than the source terminal connected to the electrode extension. The proposed source-gate multiple electrode extension (SSG-FP) structure exhibits superior breakdown characteristics, with an improvement of approximately 750 V compared to the structure without electrode extensions. The optimized gate plate dimensions are 0.75 μm, the dimension of the primary source electrode extension is 3.1 μm, and the dimension of the secondary source electrode extension is 4.1 μm. The device exhibits a threshold frequency (Ft) of 17.86 GHz and a peak oscillation frequency (Fmax) of 58.6 GHz. These findings provide guidance for designing HEMT devices with electrode extension structures.