Oxide induced degradation in MoS₂ field-effect transistors

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Transition Metal Dichalcogenides (TMDC) are crucial for next-generation transistors.
• Interface imperfections, particularly with amorphous gate oxides, limit TMDC device performance.
• Understanding these interfaces is key to advancing semiconductor technology.

Purpose of the Study:

• To investigate the impact of amorphous Al2O3 and HfO2 interfaces on monolayer to trilayer MoS2 transistors.
• To correlate atomic-scale interface features with experimentally observed performance degradation.
• To identify strategies for optimizing oxide interfaces in TMDC devices.

Main Methods:

• First principles simulations were employed to model TMDC transistors.
• Atomic-scale interface characteristics were analyzed.
• The effects of potential fluctuations and surface defects were simulated.

Main Results:

• Amorphous oxide interfaces induce potential fluctuations, reducing TMDC mobility and drive current.
• Surface defects create trap states, leading to leakage currents and increased subthreshold swing (SS).
• Trilayer MoS2 exhibits less mobility degradation than mono- and bilayer MoS2, showing increased resilience.

Conclusions:

• Atomic-scale interface variations significantly impact TMDC transistor performance.
• Optimizing amorphous oxide interfaces is essential for preserving device functionality.
• Even defect-free interfaces can lead to performance loss, highlighting the need for careful material selection and engineering.