Achieving near-zero temperature coefficient of resistivity in atomic layer deposition TiSixN films through composition tuning

Abstract

Atomic layer deposition (ALD) is used to systematically vary the composition of TiSixN films by modulating the ratio of Ti and Si precursors with NH3 as a coreactant. The as-synthesized films have varying atomic (at.) % Si (0 ≤ x ≤ 24.2) to provide both metallic (i.e., TiN) and insulating (i.e., Si3N4) behavior. The competing material properties reduce the temperature coefficient of resistivity (TCR) of the film, thereby generating a regime where electrical conductance is independent of temperature. The TiSixN (Si = 3.4 at. %) film with 139.6 nm thickness exhibits a near-zero TCR of −23 ppm K−1, between 298 and 398 K, and a resistivity of 348.1 μΩ cm. Materials characterization using x-ray reflectometry, x-ray diffraction, x-ray photoelectron spectroscopy, and Raman spectroscopy, in conjunction with van der Pauw measurement and spectroscopic ellipsometry, are conducted to characterize film properties. Correlating structural, electrical, and optical properties provides insights into the electronic interactions of TiN with Si3N4, synthesized as an ALD nanocomposite thin film.