Dissertation Defense

Investigation of Dielectric Reliability with β–Gallium Oxide for Future Power Devices

Hannah Masten

Passcode: 778678


β-Gallium Oxide (β-Ga2O3) is an exciting ultra-wide bandgap (UWBG) semiconductor with great potential in power devices due to its excellent electrical properties. The development of high-performing, stableβ-Ga2O3 metal-oxide-semiconductor (MOS) devices requires the optimization of the gate dielectric-semiconductor interface. The unique aspects of β-Ga2O3, including its ultra-large bandgap and self-trapping hole behavior, present us with many questions about its MOS reliability. In this thesis I investigate the trapping and emission of charges in MOS structures with β-Ga2O3 to answer these questions.

First, I demonstrate an alternative high-k dielectric, (Y0.6Sc0.4)2O3, with β-Ga2O3 in MOS capacitors (MOSCAPs) and analyze the interface quality between the solution-processed dielectric and the UWBG semiconductor. The techniques and analyses developed here can be utilized for further dielectric-UWBG semiconductor research. Next, positive bias stress measurements are performed on ALD HfO2/β-Ga2O3 and HfO2/Si MOSCAPs to investigate how the UWBG semiconductor impacts charge trapping and recovery. The thermal reliability of the HfO2/β-Ga2O3 interface is then investigated. Lastly, the focus shifts to vertical MOS structures on etched β-Ga2O3. HfO2/β-Ga2O3 fin MOSCAPs are fabricated and analyzed to investigate the dielectric interface quality on the sidewalls of plasma-etched β-Ga2O3, which is necessary for the further development of the β-Ga2O3 fin MOSFET.

Co-Chairs: Professor Becky (R.L.) Peterson and Professor Jamie Phillips