High-Performance GaN MOSHEMTs Fabricated With ALD Al2O3 Dielectric and NBE Gate Recess Technology for High Frequency Power Applications.

High-performance GaN metal–oxide–semi-conductor high-electron-mobility transistors (MOSHEMTs) using Al2O3 gate dielectric deposited by atomic layer deposition (ALD) and damage-free neutral beam etch (NBE) gate recess process for millimeter-wave power applications are demonstrated. The high-quality ALD Al2O3 reduces the gate leakage current of the device and the NBE method eliminates the plasma-induced defects in the nitride materials. The MOSHEMT device fabricated exhibits a high maximum drain current density ( I\textsf {DS,max} ) of 1.65 A/mm and a high peak extrinsic transconductance ( g\textsf {m.ext} ) of 653 mS/mm. The MOSHEMT device also demonstrates excellent RF performances, including fT/f\textsf {MAX}= 183 /191 GHz, NF \textsf {min}= 2.56 dB with G\textsf {AS}= 5.61 dB at 54 GHz, and an output power density of 2.7 W/mm associated with a power-added efficiency of 20.9% and a linear power gain of 9.4 dB at 38 GHz. To the best of our knowledge, the noise performance at 54 GHz is the best reported so far for the AlGaN/GaN HEMTs. [ABSTRACT FROM PUBLISHER]