DC/RF Performance and Reliability of 100-nm Gate Length AlGaN/GaN MIS-HEMTs with Different Thickness of in-situ SiN

GaN HEMTs are promising for RF applications because of their wide bandgap and high electron mobility. To achieve a rapid operation speed, scaling of gate length is necessary for RF devices. Furthermore, metal-insulator-semiconductor (MIS)-HEMTs are often used to achieve a low gate leakage current. In this work, AlGaN/GaN MIS-HEMTs with 100-nm L
G
and 15/30-nm in-situ SiN as gate dielectric were fabricated and analyzed. Typical DC and RF characteristics, and reliability evaluations including gate-lag/drain-lag measurement, were conducted. The device with thinner in-situ SiN exhibits better RF performance (
$\mathrm{f}_{\mathrm{T}}/\mathrm{f}_{Max}= 101/73$
GHz;
$\text{PAE} =38\%$
) but with a larger current drop after gate-lag/drain-lag measurements, which can be due to a higher electric field caused by the thinner dielectric.