Investigation of the Current Stability of AlGaN/GaN High Electron Mobility Transistors in Various Liquid/Solid Interface on the Gate Area

Abstract

Variation of temperature, pressure, and pH values has been demonstrated for affecting the stability of AlGaN/GaN HEMTs sensors. In addition to the factors above mentioned, we found out other factors which are related to the stability of AlGaN/GaN HEMTs sensors. In this study, we found out the current variation of AlGaN/GaN HEMTs without gate metal sensors is inversely proportional to the viscosity of liquids. We also found out that dipole moment of liquids is related to the current variation of AlGaN/GaN HEMTs without gate metal sensors. IntroductionThe III-nitride based devices, such as GaN, AlN and InN, were commonly used for sensor applications at harsh environment. Among various III-nitride based sensors, AlGaN/GaN HEMT based sensors have been demonstrated for gas, chemical, and biosensing applications 1-5 . Furthermore, AlGaN/GaN HEMT sensors have been also demonstrated for temperature and pressure sensing application. The current-voltage response to the temperature and pressure is linear 6, 7 . In addition to the application above mentioned, AlGaN/GaN HEMTs sensors have been demonstrated for measuring pH value and showed linear response to pH value between pH=2 and pH=12 8 . Therefore, the temperature, pressure and pH value are the significant factors in regard to the stability of sensors.