Ultrahigh purity plasma-enhanced atomic layer deposition and electrical properties of epitaxial scandium nitride.

This article focuses on the development and characterization of scandium nitride (ScN) thin films grown by plasma-enhanced atomic layer deposition (PEALD) using a novel precursor, bis(ethylcyclopentadienyl)scandium-chloride [ClSc(EtCp)₂], under ultrahigh purity conditions. ScN films were deposited on silicon (100), sapphire (0001), and magnesium oxide (001) substrates, with epitaxial, single-crystal cubic phase growth observed on sapphire and magnesium oxide, while polycrystalline films formed on silicon. The study identified an ALD temperature window between 200 and 215 °C, achieving films with near-stoichiometric nitrogen-to-scandium ratios and low impurity levels, and demonstrated good conformality in high aspect ratio silicon trenches. Electrical measurements showed that ScN films on MgO exhibited high electron mobility (298 cm²/V·s) and low resistivity (1.01 mΩ·cm), indicating potential for semiconductor applications.