Investigation of the Impact of 10 nm High-κ SrTiO3 Gate Dielectric on the Performance of β-Ga2O3 Metal-Oxide-Semiconductor Field-Effect Transistors

Abstract

High-κ dielectric materials have gained significant attention in the field of semiconductor devices due to their potential to reduce gate dielectric thickness while enhancing device performance. This study presents a metal-oxide-semiconductor field-effect transistor (MOSFET) that utilizes an ultrathin SrTiO₃ gate dielectric and compares it with a conventional Al₂O₃-based MOSFET. The Al₂O₃/β-Ga₂O₃ MOSFET, featuring a 10 nm gate dielectric, exhibited a high tunneling rate, significantly affecting the depletion of β-Ga₂O₃. In contrast, the SrTiO₃-based MOSFET demonstrated a lower tunneling rate, reduced reverse drain current, and improved drain on/off ratio, highlighting the effectiveness of high-κ materials like SrTiO₃ in minimizing gate dielectric thickness and potentially extending Moore’s law. Detailed analysis of the depletion and channel formation mechanisms in the SrTiO₃/β-Ga₂O₃ MOSFET was performed. Additionally, the impact of various gate metals on device performance was investigated, revealing that high-work-function metals enabled more efficient depletion compared to low-work-function metals. Temperature-dependent simulations using titanium (Ti) and platinum (Pt) as contact metals indicated that Pt-based MOSFETs operate effectively at elevated temperatures, unlike Ti-based MOSFETs. Lastly, the study examined the effects of interfacial charge types and densities at the SrTiO₃/β-Ga₂₃ interface on the MOSFET performance.