Ga2O3-Based Devices for High Power Switching Applications

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