Friday, January 3, 2025

Breakthrough in Semiconductor Technology: Amorphous ALD Deposited Nanometal Film Enhances Miniaturization Efficiency

A joint research team from Ajou University in Korea and Stanford University in the US has developed a groundbreaking semiconductor material using an amorphous semi-metallic thin film. Unlike traditional metals that suffer from increased resistivity as they get thinner, this newly discovered material exhibits decreased resistivity when its thickness is reduced. This characteristic addresses a critical challenge in semiconductor miniaturization, where the narrowing of circuit lines impedes electron movement and hampers performance. The material is created by layering niobium (Nb) crystals on a sapphire lattice and covering it with amorphous niobium phosphide (NbP). The research, published in Science, demonstrates that this new material outperforms existing metals like copper and tantalum when the thickness drops below 10 nm, providing a promising solution for next-generation semiconductors.

This amorphous thin film is notable for its compatibility with current semiconductor fabrication processes and its ability to enhance performance without requiring high-temperature treatments. The team plans to further optimize the process using atomic layer deposition (ALD), a method that ensures precise control over film thickness at the atomic scale, making it ideal for advanced semiconductor miniaturization. Professor Oh Il-gwon, who led the research, emphasized the material's potential to overcome existing limitations in semiconductor technologies and its role in securing future industry leadership. This discovery is expected to revolutionize semiconductor wiring processes, improving both efficiency and production costs in the race for smaller, faster, and more efficient chips.

Editor’s summary

Noncrystalline semimetal niobium phosphide has greater surface conductance as nanometer-scale films than the bulk material and could enable applications in nanoscale electronics. Khan et al. grew noncrystalline thin films of niobium phosphide—a material that is a topological semimetal as a crystalline material—as nanocrystals in an amorphous matrix. For films with 1.5-nanometer thickness, this material was more than twice as conductive as copper. —Phil Szuromi

Abstract

The electrical resistivity of conventional metals such as copper is known to increase in thin films as a result of electron-surface scattering, thus limiting the performance of metals in nanoscale electronics. Here, we find an unusual reduction of resistivity with decreasing film thickness in niobium phosphide (NbP) semimetal deposited at relatively low temperatures of 400°C. In films thinner than 5 nanometers, the room temperature resistivity (~34 microhm centimeters for 1.5-nanometer-thick NbP) is up to six times lower than the resistivity of our bulk NbP films, and lower than conventional metals at similar thickness (typically about 100 microhm centimeters). The NbP films are not crystalline but display local nanocrystalline, short-range order within an amorphous matrix. Our analysis suggests that the lower effective resistivity is caused by conduction through surface channels, together with high surface carrier density and sufficiently good mobility as the film thickness is reduced. These results and the fundamental insights obtained here could enable ultrathin, low-resistivity wires for nanoelectronics beyond the limitations of conventional metals.



Sources: 

Surface conduction and reduced electrical resistivity in ultrathin noncrystalline NbP semimetal | Science

Korean and American researchers develop new semiconductor material enhancing performance - CHOSUNBIZ

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