Enhancement-mode AlGaN/GaN HEMTs with high linearity fabricated by hydrogen plasma treatment

Enhancement-mode (E-mode) AlGaN/GaN high electron mobility transistors (HEMTs) are highly desirable for power and digital electronic circuits. Several technologies have been demonstrated in the last few years to fabricate E-mode devices. For example, gate recess can be applied to conventional AlGaN/GaN HEMTs to achieve E-mode operation. However, these devices have very low threshold voltage and large gate leakage. Alternatively, the use of CF4 plasma treatment in the gate region prior to gate metallization resuIts in E-mode AlGaN/GaN HEMTs with higher threshold voltage. In this paper, we demonstrate E-mode AlGaN/GaN HEMTs by hydrogen plasma treatment. The results are compared to the F-treated HEMTs an d depletion-mode (D-mode) HEMTs and important differences have been found in the linearity of these transistors.