Substrate temperature effect on growth behavior and microstructure-properties relationship in amorphous Ni[sbnd]Nb thin films

Abstract

The effect of substrate temperature on growth behavior and microstructure-properties correlation of magnetron sputtered Ni60Nb40 films were systematically investigated. With substrate temperature increasing from 293 K to 493 K, and thickness changing from 50 nm to 1 μm, all films kept in amorphous state. The characteristic of columnar growth was clearly seen, with reduced interfacial fraction between adjacent columns and increased granule size at high substrate temperature. Through scaling analysis, films deposited at all temperatures grow in an anomalous roughening mode, and at 293 K for films thicker than 200 nm, a difficult roughening phenomenon was revealed. High substrate temperature can facilitate the surface kinetic roughening. Both decreased interface fraction-to-volume ratio by particle coarsening and reduced free volume by structure relaxation caused the dense atomic atomic packing and increased density, which may be the crucial reason for enhanced mechanical properties and thermal stability against crystallization.