Nondestructive Method for Mapping Metal Contact Diffusion in In2O3 Thin-Film Transistors

Area of Science:

• Materials Science
• Electrical Engineering
• Semiconductor Physics

Background:

• The channel width-to-length ratio is a critical transistor parameter influencing integrated circuit performance.
• Contact diffusion into the transistor channel can alter this crucial parameter during fabrication or operation.
• Existing methods struggle to detect subtle diffusion, especially at semiconductor interfaces.

Purpose of the Study:

• To develop a novel, non-destructive methodology for detecting contact diffusion in active semiconductor devices.
• To enable the characterization of diffusion effects on critical transistor parameters.
• To improve the reliability and performance of integrated circuits through precise defect detection.

Main Methods:

• Combining atomic force microscopy (AFM) and scanning Kelvin probe microscopy (SKPM) for surface potential mapping.
• Utilizing self-consistent modeling with physically based Technology Computer Aided Design (TCAD) simulations.
• Incorporating transistor terminal biasing (grounded and biased conditions) and tip geometry effects in simulations.

Main Results:

• Successful non-destructive detection of contact diffusion on active devices.
• Modeling of surface potential scans accurately reflects experimental measurements under various conditions.
• Demonstrated sensitivity to potential contrast below typical scanning probe microscopy detection limits.

Conclusions:

• The developed AFM/SKPM and TCAD modeling methodology offers a powerful tool for analyzing contact diffusion.
• This technique is particularly valuable for semiconductor and metal-semiconductor interfaces.
• It enables improved quality control and understanding of diffusion-related device degradation.