Ti-Si-N diffusion barriers between silicon and copper

Abstract

Thin films of Ti-Si-N, reactively spattered from a Ti/sub 5/Si/sub 3/ target, are assessed as diffusion barriers between silicon substrates and copper overlayers. By tests on shallow-junction diodes, a 100 nm Ti/sub 34/Si/sub 23/N/sub 43/ barrier is able to prevent copper from reaching the silicon substrate during a 850/spl deg/C/30 min anneal in vacuum. A 10 nm film prevents diffusion up to 650/spl deg/C/30 min. By high-resolution transmission electron microscopy, Ti/sub 34/Si/sub 23/N/sub 43/ predominantly consists of nanophase TiN grains roughly 2 nm in size.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>