Investigation of?AlGaN/GaN HEMT?and Its Sensor Electronic Applications

Abstract

In this thesis aluminum gallium nitride/gallium nitride high electron mobility transistor (AlGaN/GaN HEMT) covered with silicon nitride passivation on silicon substrate were fabricated the experimental topic is divided into two main part The effect of different silicon nitride passivation layer thickness on the AlGaN/GaN HEMT and the sensing application of in gas and UV detecting by Zinc oxide nanorod gated AlGaN/GaN based HEMT sensor In the first topic devices with different thickness of silicon nitride passivation layer were fabricated by the same process By using low pressure chemical vapor deposition (LPCVD) process silicon nitride was grown on the AlGaN/GaN HEMT structure with two different thickness 8nm and 16nm In order to compare the different thickness of the passivation layer the I-V characteristic were measured Showing the device with thicker silicon nitride passivation has the better performance not only depress the leakage current of the gate but also has positive threshold voltage shift and exhibits better I-V curves at the saturation states The second part demonstrate the sensing application of AlGaN/GaN HEMT ZnO nanorod microstructure was synthesized by using simple hydrothermal method The ZnO nanorods were used to fabricate a gas sensor to detect ethanol vapor It is also capable for UV detecting as a photodetector From the measurement results AlGaN/GaN HEMT based sensor with ZnO nanorod has high reversible and fast response to ethanol and exhibited sensitive responsivity as photodetector demonstrating great potential application as a multiple function sensor

Date of Award	2017 Jul 5
Original language	English
Supervisor	Shoou-Jinn Chang (Supervisor)