AlGaN/GaN MIS-HEMT gate structure improvement using Al_2O_3 deposited by plasma-enhanced ALD

摘要

In this work we evaluate the influence of the Al_2O_3 ALD deposition technique on AlGaN/GaN MIS-HEMT structures. It has been found that using O_2 plasma as oxidizer instead of water could increase the threshold voltage considerably while greatly reducing gate leakage current. C(V) measurements have shown a very fast on/off transition even at 1 kHz, with low frequency dispersion, while a record slope of 80 mA/ decades was achieved between the on and off states through I_dd(V_g) measurements. Gate leakage currents were also drastically reduced with a measured average of le~(-11)A/mm for a drain-source bias of 5 V.