Scale-robust Low Resistance Transport in Atomic Layer Deposited Topological Semimetal Wafers on Amorphous Substrate

TL;DR

This paper reports the first wafer-scale growth of amorphous topological semimetal TaP via atomic layer deposition on amorphous substrates, showing surface-dominated conduction and promising applications in energy-efficient electronic interconnects.

Contribution

It introduces a novel low-temperature ALD process for amorphous TaP films with unique resistivity scaling and demonstrates their potential for scalable, low-power interconnects in electronics.

Findings

Resistivity decreases with decreasing film thickness.

Ultrathin films exhibit surface-dominated conduction.

Films show thermal stability up to 600°C.

Abstract

As data-centric computing advances, energy-efficient interconnects are increasingly critical for AI-driven systems. Traditional metal conductors face severe limitations at nanoscale due to increased resistivity from surface scattering. In response, this study demonstrates the first wafer-scale realization of an amorphous topological semimetal, tantalum phosphide (TaP), grown directly on amorphous SiO2 substrates (without any seed layers) using low-temperature atomic layer deposition (ALD). The resulting TaP films exhibit unconventional resistivity scaling: decreasing resistivity with decreasing thickness, reaching 227 micro-ohm cm at ~2.3 nm film thickness. This behavior, observed without crystalline order or seed layers, indicates dominant surface conduction and establishes ALD-TaP as a promising candidate for back-end-of-line integration. The films also show excellent conformality, stoichiometry control, and thermal stability up to 600 degree C. A two-channel conduction model confirms surface-dominated transport in ultrathin regimes, further supported by enhanced conductivity in multi-stacked configurations. These findings highlight the potential of amorphous topological semimetals for future high-density, low-power electronic interconnects and expand the applicability of ALD for integrating novel quantum materials at scale.