Stability and Reliability of van der Waals High-κ SrTiO₃ Field-Effect Transistors with Small Hysteresis

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanoelectronics

Background:

• Two-dimensional (2D) field-effect transistors (FETs) require reliable gate insulators for enhanced performance.
• Single-crystal strontium titanate (SrTiO3 or STO) is an ultrahigh-κ dielectric with potential for high breakdown strength and low interface trap density.

Purpose of the Study:

• To investigate the performance, stability, and reliability of MoS2 FETs utilizing STO as a gate insulator.
• To assess the potential of STO to improve the reliability of 2D nanoelectronic devices.

Main Methods:

• Fabrication and characterization of MoS2 field-effect transistors with single-crystal STO gate insulators.
• Electrical performance testing, including analysis of hysteresis, sweep rate dependence, and bias temperature instability (BTI).

Main Results:

• Observed minimal hysteresis in MoS2/STO FETs up to 8 MV cm⁻¹, with reproducible dynamics over extended periods.
• Anomalous counterclockwise hysteresis and BTI suggest oxygen vacancy diffusion as a likely cause.
• Demonstrated high reliability of MoS2/STO FETs, indicating STO's suitability for demanding applications.

Conclusions:

• Single-crystal STO is a highly promising gate insulator for advancing the reliability of 2D nanoelectronics.
• STO's properties may help overcome critical challenges in the development of next-generation 2D FETs.