An enhancement-mode (E-mode) AlGaN/GaN high electron mobility transistor (HEMTs) was fabricated with 15-nm AlGaN barrier layer.E-mode operation was achieved by using fluorine plasma treatment and post-gate rapid thermal annealing.The thin barrier depletion-HEMTs with a threshold voltage typically around-1.7 V,which is higher than that of the 22-nm barrier depletion-mode HEMTs (-3.5 V).Therefore,the thin barrier is emerging as an excellent candidate to realize the enhancement-mode operation.With 0.6-μm gate length,the devices treated by fluorine plasma for 150-W RF power at 150 s exhibited a threshold voltage of 1.3 V.The maximum drain current and maximum transconductance are 300 mA/mm,and 177 mS/mm,respectively.Compared with the 22-nm barrier E-mode devices,V T of the thin barrier HEMTs is much more stable under the gate step-stress. An enhancement mode (E-mode) AlGaN / GaN high electron mobility transistor (HEMTs) was fabricated with 15-nm AlGaN barrier layer. E-mode operation was achieved by using fluorine plasma treatment and post-gate rapid thermal annealing. Thin barrier depletion-HEMTs with a threshold voltage typically around-1.7 V, which is higher than that of the 22-nm barrier depletion-mode HEMTs (-3.5 V) .herefore, the thin barrier is emerging as an excellent candidate to realize the enhancement -mode operation. Six 0.6-μm gate length, the devices treated by fluorine plasma for 150-W RF power at 150 s exhibited a threshold voltage of 1.3 V. The maximum drain current and maximum transconductance are 300 mA / mm, and 177 mS /mm, andrespectively. Compared with the 22-nm barrier E-mode devices, VT of the thin barrier HEMTs is much more stable under the gate step-stress.