AlGaN/GaN MIS-HEMT gate structure improvement using Al2O3 deposited by Plasma-Enhanced ALD

In this work we evaluate the influence of the Al2O3 ALD deposition technique on AlGaN/GaN MIS-HEMT structures. It has been found that using O2 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 1kHz, with low frequency dispersion, while a record slope of 80mA/ decades was achieved between the on and off states through Id(Vg) measurements. Gate leakage currents were also drastically reduced with a measured average of 1e -11 A/mm for a drain-source bias of 5V.