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

Passcode: 778678

Abstract:

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, (Y_0.6Sc_0.4)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