MORPHOLOGY OF TISI2 FILMS ON SI FORMED FROM CO-DEPOSITED TI AND SI

Titanium disilicide (TiSi2) films formed from varying compositions of co-deposited Ti and Si on a Si substrate and annealed in argon at 850 degrees C have been characterized by Rutherford backscattering, Auger electron spectroscopy, transmission electron microscopy, atomic force microscopy, and high resolution X-ray diffraction. As-deposited films (TiSix) with x < 2 form a TiOxN1-x film on top of a TiSi2 film after a nnealing, while ''Si-rich'' (x > 2) film form TiSi2 with a poly Si fil m on top. This result is explained by the strong driving force of Ti t o form an oxide or nitride with ambient gases while Si must diffuse th rough the growing film to form TiSi2. An ''Si-rich'' as-deposited comp osition (x > 2) results in less interface roughening between the TiSi2 film and Si substrate after annealing, as well as greater residual wa fer curvature as compared to the other samples, The reduced wafer curv atures in the ''Si-deficient'' samples is attributed to the presence o f the TiOxN1-x film which acts to counter the stress in the TiSi2 film . (C) 1997 Elsevier Science S.A.