Photoluminescence characterization of the quantum well structure and influence of optical illumination on the electrical performance of AlGaN/GaN modulationhyphen;doped fieldhyphen;effect transistors

摘要

Electrical characteristics of high performance GaN modulationhyphen;doped fieldhyphen;effect transistors (MODFETs) grown by reactive molecular beam epitaxy method are studied experimentally both in dark and under white light illumination. The maximum measured drainhyphen;source current is 626 mA/mm in dark and 695 mA/mm under illumination, which saturates at a relatively low drainhyphen;source voltageVDS. The transconductance increases with decreasing gate length reaching a value of 210 mS/mm in dark and 222 mS/mm under illumination for devices with a gate length ofLG=1.5mgr;m. Breakdown voltages of about 90 V have also been exhibited by devices with gate lengthLG=1.5 mgr;m and drainhyphen;gate distanceLDG=1 mgr;m. 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. copy;1996 American Institute of Physics.