Improved Self-Heating in Short-Channel Monolayer WS₂ Transistors with High-Thermal Conductivity BeO Dielectrics

Area of Science:

• Materials Science
• Semiconductor Physics
• Nanotechnology

Background:

• Two-dimensional semiconducting transition metal dichalcogenides (TMDs) offer atomic-thin channels for advanced transistor technology.
• Self-heating effects in ultrathin TMD channels limit current density and device reliability, potentially causing negative differential resistance.

Purpose of the Study:

• To investigate the impact of high-thermal-conductivity dielectrics on mitigating self-heating in monolayer WS₂ transistors.
• To achieve high-performance transistors by suppressing negative differential resistance.

Main Methods:

• Fabrication of monolayer WS₂ field-effect transistors on beryllium oxide (BeO) and hafnium oxide (HfO₂) dielectrics.
• Characterization of device performance, including on-state current, transconductance, and on/off ratio under varying electric fields.
• Comparative analysis of self-heating suppression between BeO and HfO₂ dielectrics.

Main Results:

• Monolayer WS₂ transistors on BeO exhibited significantly suppressed self-heating effects compared to those on HfO₂.
• The BeO-based devices eliminated the negative differential resistance behavior observed at high electric fields.
• Record-high performance metrics were achieved: 325 μA/μm on-state current, 150 μS/μm transconductance, and 1.8 × 10⁸ on/off ratio at 1 V.

Conclusions:

• High-thermal-conductivity BeO is an effective dielectric for suppressing self-heating in monolayer WS₂ transistors.
• This approach enables high-performance and reliable ultrathin channel transistors for future electronic applications.