Improving the Stability of High-Performance Multilayer MoS₂ Field-Effect Transistors.

Area of Science:

• Materials Science
• Nanotechnology
• Solid-State Electronics

Background:

• Multilayer molybdenum disulfide (MoS₂) field-effect transistors (FETs) are promising for next-generation electronics.
• However, their stability and hysteresis issues hinder practical applications.
• Improving device reliability without sacrificing performance is crucial.

Purpose of the Study:

• To develop a method for enhancing the stability and reducing hysteresis in multilayer MoS₂ FETs.
• To maintain the high electrical performance of MoS₂ FETs.
• To investigate the impact of O₂ plasma treatment and Al₂O₃ passivation on device characteristics.

Main Methods:

• Multilayer MoS₂ FETs were treated with O₂ plasma for varying durations (30s, 90s, 120s).
• Al₂O₃ encapsulation was applied post-plasma treatment.
• Electrical characteristics and gate-bias stress tests were performed to evaluate device performance and stability.

Main Results:

• A 30s O₂ plasma treatment followed by Al₂O₃ passivation resulted in reduced hysteresis and maintained high performance.
• An intermediate MoO_x layer formed during plasma treatment was identified as key to preventing excess carrier generation.
• Prolonged plasma exposure (90s, 120s) led to increased hysteresis and off-current due to excess oxygen in the MoO_x layer.
• Devices showed negligible performance degradation under most bias stress conditions, except for negative bias illumination stress, indicating sulfur vacancies.

Conclusions:

• Optimized O₂ plasma treatment and Al₂O₃ passivation offer a viable route to stable, high-performance, hysteresis-free MoS₂ FETs.
• The findings provide insights into the role of the MoO_x interlayer in device stability.
• This approach is applicable to other transition metal dichalcogenide materials, paving the way for advanced electronic applications.