Edge-Contact MoS₂ Transistors Fabricated Using Thermal Scanning Probe Lithography

Area of Science:

• Materials Science and Engineering
• Nanotechnology
• Semiconductor Device Fabrication

Background:

• Two-dimensional materials (2DMs), especially 2D semiconductors, are crucial for next-generation electronics.
• Conventional fabrication methods like electron beam lithography can damage delicate 2DMs, degrading their properties.
• Gentle fabrication techniques are needed to preserve the integrity of 2DMs during device integration.

Purpose of the Study:

• To demonstrate the use of thermal scanning probe lithography (t-SPL) for fabricating molybdenum disulfide (MoS2)-based field-effect transistors (FETs).
• To specifically showcase t-SPL for creating edge-contact MoS2 FETs, a novel application.
• To achieve high-performance characteristics in MoS2 FETs fabricated with a non-damaging lithography technique.

Main Methods:

• Utilized thermal scanning probe lithography (t-SPL) for patterning and Ar+ milling for etching the MoS2.
• Integrated etching and metal deposition steps within a single vacuum process to prevent atmospheric contamination.
• Fabricated edge-contact MoS2 FETs using a combination of hot-tip patterning and Ar+ milling.

Main Results:

• Successfully fabricated functional edge-contact MoS2 FETs using the developed t-SPL process.
• Achieved high on/off ratios of up to 10^8 at room temperature in air.
• Observed even higher on/off ratios, reaching 10^9 in vacuum, comparable to state-of-the-art devices.

Conclusions:

• Thermal scanning probe lithography is a viable and gentle method for fabricating high-performance 2D semiconductor devices like MoS2 FETs.
• The t-SPL technique, combined with in-situ processing, effectively preserves the quality of MoS2, leading to excellent device performance.
• This approach offers a promising alternative for the scalable and reliable manufacturing of advanced 2D electronic devices.