Crystallization of Si3N4 layers and its influences on the microstructure and mechanical properties of ZrN∕Si3N4 nanomultilayers

Abstract

Zr N ∕ Si 3 N 4 nanomultilayers with different layer thicknesses of Si3N4 were synthesized to study the crystallization of Si3N4 and its effects on the microstructure and mechanical properties of multilayers. Results indicated that influenced by the template effects of crystalline ZrN layers, amorphous Si3N4 layers were crystallized into a rocksaltlike pseudocrystal structure when their thickness was less than 0.9nm. Then crystallized Si3N4 layers grew epitaxially with ZrN and formed strong columnar crystals, accompanied with a remarkable increase in hardness. When its thickness exceeds 1.1nm, the subsequently deposited Si3N4 grows as amorphous, blocking the epitaxial growth and leading to a quick decline of hardness.