Factors which determine the orientation of CVD Al films grown on TiN

CVD Al deposited on a TiN/Ti liner followed by 'warm' PVD Al (Cu) is a prom ising approach for filling high aspect ratio vias. A highly (111) textured film is important to achieve high electromigration resistivity. The depende nce of the Al orientation on the type of the underlying TIN liner and the m echanism responsible for this effect were investigated. HRTEM was used to c haracterize the structure of the Al grains (after 1 s of deposition), throu gh to a continuous film, as well as the structure of the interface of thick Ai films with TiN. The microscopy results helped to explain the X-ray diff raction observations that on PVD TIN the Al film had a stronger (111) textu re than on other TiN types. This is attributed to a topotaxial relationship , which forms during the nucleation stage of the CVD Al. (C) 1999 Elsevier Science Ltd. All rights reserved.