Improved Power Device Figure-of-Merit ($4.0\times 10^{8}$ V$^{2}$ $\Omega^{-1}$ cm$^{-2}$) in AlGaN/GaN High-Electron-Mobility Transistors on High-Resistivity 4-in. Si

Abstract

The OFF-state breakdown voltage (BVgd) characteristics of AlGaN/GaN high-electron-mobility transistors (HEMTs) on a 4-in. Si substrate were investigated and analyzed. The HEMTs with Lgd = 10 µm exhibited BVgd of 723 V with the specific on-resistance RDS[ON] of 1.3 mΩ cm2. Due to the improved ohmic contact, the devices exhibited low RDS[ON] values. The power device figure-of-merit (FOM=BVgd2/RDS[ON]) is as high as 4.0×108 V2 Ω-1 cm-2, the highest among the reported values for GaN HEMTs on a 4-in. Si. Due to the low vertical buffer leakage current, a high vertical breakdown voltage of ∼1200 V has been achieved with the total buffer thickness (dBuff) of 2.2 µm.