Highly Oriented and Stress Modified Thick AlN Films Deposited on Low Thermal Expansion Alloy Substrates for Flexible Electronics in Harsh Environment

Abstract

Highly oriented and stress-modified thick aluminium nitride (AlN) films were deposited by reactive AC magnetron sputtering on 4 inch substrates and foils made of the low thermal expansion alloy "42Alloy" for flexible electronics in harsh environment. As a result of modification of film depositing conditions for reducing residual stress, a flat three micrometer thick AlN film was deposited successfully on the 50 μm thick 42Alloy foil, and its full width at half maximum of AlN(002) was 5.00 degree. And, it was confirmed that the AlN films on 42Alloy foils have piezoelectricity by measurement of a tip displacement of the cantilever-shape test structure.