Mobility Extraction in 2D Transition Metal Dichalcogenide Devices-Avoiding Contact Resistance Implicated...

Area of Science:

• Semiconductor Device Physics
• Materials Science

Background:

• Schottky barrier (SB) transistors differ from conventional MOSFETs, with gate control over carrier injection from source/drain contacts.
• The impact of contact gating on SB transistors in the on-state, affecting intrinsic channel property evaluation, remains understudied.

Purpose of the Study:

• To comprehensively investigate the on-state contact gating effects in Schottky barrier transistors.
• To analyze the influence of contact resistance and dual threshold voltages on device performance metrics.

Main Methods:

• Detailed experimental analysis of Schottky barrier transistors.
• Evaluation of effects from varying effective oxide thicknesses, Schottky barrier heights, and doping concentrations.

Main Results:

• Contact resistance (R_C) is inherently gate-dependent in back-gated structures, invalidating traditional field-effect mobility (μ_FE) extraction from maximum transconductance (g_m).
• The presence of two distinct threshold voltages (channel and contact) complicates accurate carrier concentration (n_s) calculations.
• Traditional methods can overestimate mobility and lead to inaccuracies in device characterization.

Conclusions:

• On-state contact gating significantly impacts Schottky barrier transistor characterization.
• Accurate device metrics require accounting for gate-dependent contact resistance and dual threshold voltages.
• Understanding these effects is crucial for reliable Schottky barrier transistor design and analysis.