Dissertation Defense

Ga2O3-Based Devices for High Power Switching Applications

Zhe (Ashley) Jian
1200 EECS BuildingMap

Passcode: 142262

The need for efficient power generation, distribution, and delivery is quickly expanding in different sectors of industry. Power electronics is at the heart of this industrial revolution, which can be found in various applications ranging from solar inverters, electric vehicles, and motor servos. Ga2O3 is emerging as an attractive semiconductor for high-power switching applications. This dissertation is focused on addressing three critical issues in Ga2O3-based device technology.

(i) Thermal stability of Schottky contacts to enable high power applications in harsh environments. Temperature-dependent behavior of Ga2O3 trench Schottky barrier diodes (SBD) was studied and was compared with regular SBDs. The trench SBDs showed superior thermal stability compared with that on regular SBDs. (ii) A robust dielectric to take full advantage of high breakdown field of Ga2O3. I investigated two dielectrics, including ALD Al2O3 and MOCVD AlSiO. Negligible hysteresis, low interfacial trap density, low leakage current, and record-high breakdown electric field were achieved on AlSiO/Ga2O3 MOSCAPs, making MOCVD AlSiO a promising dielectric for high power Ga2O3 electronic devices. (iii) Heterogeneous integration of Ga2O3 and GaN substrates. In order to address some of main drawbacks of Ga2O3 such its relatively low electron mobility and unavailability of p-type doping, heterogeneous bonding of Ga2O3 and GaN substrates was studied. I demonstrated, for the first time, successful direct bonding of GaN and Ga2O3. The bonded-interface quality was characterized using high-resolution transmission electron microscopy (HRTEM) and extensive temperature-dependent I-V measurements. The impact of high temperature annealing on the interface quality was also investigated.

Chair:  Professor Elaheh Ahmadi