3/22/2023 0 Comments Relation between ion and ioff![]() ( a) Schematic cross-sectional structure of the p-GaN gate HEMT with an Al 0.5GaN etch-stop layer design. Therefore, high-performance normally off p-GaN/AlGaN/GaN HEMTs can be realized using an AlGaN etch-stop layer for high-speed and high-power electronic applications. Transmission electron microscopy (TEM) images revealed the etch-stop layer to be smooth and highly selective. The experimental results indicated that the dynamic R ON was improved and that the leakage current was suppressed. In this study, we applied an Al 0.5GaN etch-stop layer between p-GaN and AlGaN barriers and compared its performance with that of an AlN etch-stop layer. In tradition structures, an AlN layer is used as an etch-stop layer however, high-quality thin AlN has difficulty achieving epitaxy control, and problems related to lattice mismatch can arise. Moreover, if the p-GaN layer is overetched in to the AlGaN barrier layer and reduces the AlGaN barrier thickness in this process, the channel carrier density is decreased because of the decrease in spontaneous polarization. The precision and lower damage etching process is a key factor in device fabrication, and outstanding etching depth control is imperative because the residual p-GaN layer in the out-of-gate area makes the 2DEG channel depleted and leads to a low forward current. However, structures involving p-type gates have drawn increasing attention in industry owing to their low on-state resistance and high threshold voltage. Thus, several methods have attempted to realize the positive threshold voltage (V TH) of AlGaN/GaN HEMTs, such as ultrathin barriers, gate-recessed structures, fluorine treatment, and p-type gates. To get realistic power supply applications, the normally off behavior of GaN-based HEMTs must be implemented. In recent years, the wide bandgap (WBG) GaN-based high-electron-mobility transistors (HEMTs) have attracted much attention for high-radio-frequency (RF) and high-power semiconductor device applications owing to their excellent performance of high electric field strength (3.3 MV/cm), high mobility (>1200 cm 2/Vs), and favorable thermal conductivity. ![]()
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