ORIENTATION CONTROL OF CHEMICAL-VAPOR-DEPOSITION TIN FILM FOR BARRIERAPPLICATIONS

A chemical vapor deposition (CVD) TiN film with preferred <111> crysta l orientation was developed using an in situ two-step process scheme. A thin CVD TiN layer is deposited first under low TiCl4 partial pressu re. This layer has poor step coverage, but acts as a crystallographic seed layer for the subsequent CVD TiN layer deposited under high TiCl4 partial pressure. This layer, deposited sequentially without breaking vacuum, shows a TiN <111> preferred orientation when deposited under these conditions and provides excellent step coverage. This CVD TiN la yer ''stack'' has shown both excellent diffusion barrier properties to CVD Cu, and improved electromigration reliability relative to convent ional CVD TiN using TiCl4/NH3 chemistry.