Search

In this paper, we demonstrate the AlGaN/GaN high electron mobility transistors (HEMTs) on Si substrate using an AlGaN back-barrier (BB) and super-lattice (SL) buffer to achieve high breakdown and low current collapse (CC) properties for Radio-frequency (RF) applications. The HEMTs also demonstrated low initial vertical leakage current, high thermal stability, and smaller drain-lag with reduced leakage currents as compared to the devices using step-graded (SG) AlGaN buffer. Also, the device showed improved RF performances with higher f T and f max as compared to the devices with SG buffer.

An AlGaN/GaN/Si high electron mobility transistor (HEMT) using a GaN:C buffer with a 2 nm AlGaN electron-blocking layer (EBL) is investigated for the first time for millimeter-wave applications. Compared with the double heterostructure field effect transistor (DHFET), the AlGaN/GaN HEMT with the GaN:C/EBL buffer has a lower vertical leakage, higher thermal stability, and better RF performance. In addition, AlGaN EBL can prevent carbon-related traps from GaN:C and improve electron confinement in 2DEG during high-frequency operation. Finally, a Pout of 31.2 dBm with PAE of 21.7% were measured at 28 GHz at 28 V. These results demonstrated the great potential of HEMTs using GaN:C with AlGaN EBL epitaxy technology for millimeter-wave applications.