Combinatorial Search for Low Resistivity Pd–Cu–Si Thin Film Metallic Glass Compositions

Abstract

A new combinatorial method to deposit thin films using an arc plasma, Combinatorial arc plasma deposition (CAPD), was applied to search for low resistivity compositions of Pd–Cu–Si thin film metallic glasses (TFMGs). The CAPD setup includes three arc plasma guns (APGs), with each gun shooting a pulse-like plasma of Pd, Cu or Si at specific time intervals to deposit a Pd–Cu–Si thin film on an SiO2 substrate. In this study, a Pd-based compositionally-graded thin film was deposited by controlling the number of shots as well as the plasma strength. The deposited thin film was separated into 1,089 samples (thin film library), and the thickness, composition, phase, and relative resistivity of each sample was evaluated without detaching them from the library. From the samples, three amorphous, low relative resistivity CAPD samples were identified. To verify that these samples were metallic glasses, their compositions were reproduced in samples deposited by sputtering, and their Tg (glass transition temperature) and Tx (crystallization temperature) were measured. The absolute resistivities of the three metallic glass samples were also measured. As the result, the Pd81Cu5Si14 at. % sample showed the lowest absolute resistivity of 64 µ Ω ·cm and a supercooled liquid region temperature range ( ΔTx=Tx-Tg) of 50 K. This resistivity is 17% lower and the supercooled liquid region is almost two times larger than those of the known Pd-based TFMG composition.