Quasi-2D high mobility channel E-mode β -Ga2O3 MOSFET with Johnson FOM of 7.56 THz·V

In this Letter, an enhancement mode (E-mode) β-Ga2O3 metal-oxide-semiconductor field-effect transistor (MOSFET) with quasi-two-dimensional channel was reported, and the channel mobility of 147.5 cm2/(V·s) is achieved. Low damage etching technology and low Ohmic contact resistance technology are introduced. As a result, the E-mode transistor demonstrates a maximum drain to source current (ID) of 230.5 mA/mm, a peak transconductance (Gm) of 54.2 mS/mm, a current gain cut-off frequency (fT) of 18 GHz, and a power gain cut-off frequency (fMAX) of 42 GHz. Additionally, a positive threshold voltage (VT) of 1.65 V, a breakdown voltage (VBK) of 420 V, and a specific on-resistance (RON,SP) of 1.24 mΩ·cm2 are achieved. Moreover, a fMAX × VBK of 17.64 THz·V and a fT × VBK of 7.56 THz·V are found to be a close value so far to the theoretical limit of β-Ga2O3. This device leads to excellent radio frequency (RF) characteristics, which paved the way for future millimeter-wave RF power electronics applications with β-Ga2O3 MOSFET.