The drain current fluctuation of ungated AlGaN/GaN high electron mobility transistors (HEMTs) measured in different fluids at a drain-source voltage of 0.5 V was investigated. The HEMTs with metal on the gate region showed good current stability in deionized water, while a large fluctuation in drain current was observed for HEMTs without gate metal. The fluctuation in drain current for the HEMTs without gate metal was observed and calculated as standard deviation from a real-time measurement in air, deionized water, ethanol, dimethyl sulfoxide, ethylene glycol, 1,2-butanediol, and glycerol. At room temperature, the fluctuation in drain current for the HEMTs without gate metal was found to be relevant to the dipole moment and the viscosity of the liquids. A liquid with a larger viscosity showed a smaller fluctuation in drain current. The viscosity-dependent fluctuation of the drain current was ascribed to the Brownian motions of the liquid molecules, which induced a variation in the surface dipole of the gate region. This study uncovers the causes of the fluctuation in drain current of HEMTs in fluids. The results show that the AlGaN/GaN HEMTs may be used as sensors to measure the viscosity of liquids within a certain range of viscosity.
The microwave and low frequency noise characteristics of 6 inch InAlN/AlN/GaN high electron mobility transistor (HEMT) were demonstrated and investigated on silicon-on-insulator (SOI) substrate for the first time. The InAlN HEMT on SOI substrate was grown by metal organic chemical vapor deposition (MOCVD) on a p-type (111) Si SOI substrate with a p-type (100) Si handle wafer for possible heterogeneous integration. The Raman spectroscopy measurement indicates that the smaller epitaxy stress was obtained by adopting SOI wafer and X-ray diffraction measurements revealed that InAIN HEMT on SOI achieves a flat surface and an abrupt heterointerface. The InAlN HEMT on SOI exhibits a lower leakage current compared to the device on high resistivity (HR) Si substrate and thus improves the off-state breakdown voltage from 134 V to 198 V. Moreover, the buried SiO2 in SOI substrate also efficiently suppresses the signal loss resulting in the better bandwidth and the microwave power performance. Based on the low frequency noise measurement, InAlN HEMT on SOI substrate also performs a relatively slight degradation after hot carrier stress.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.