Suppression of leakage currents and their effect on the electrical performance of AlGaN/GaN modulation doped field-effect transistors

Electrical characteristics of high performance of AlGaN/GaN modulation doped field-effect transistors (MODFETs) grown by reactive molecular beam epitaxy method are studied experimentally. The maximum measured drain-source current is 490 mA/mm, which saturates at a relatively low drain-source voltage VDS. The transconductance increases with decreasing gate length reaching a value of 186 mS/mm in devices with a gate length of LG=2 μm. Breakdown voltages of about 90 V have also been exhibited by devices with gate length LG=2 μm and drain-gate separation LDG=1 μm. To our knowledge, these are the best values obtained so far from GaN MODFETs which we attribute to the suppression of leakage currents and improved materials structure of the devices.