Failure mechanism for metalorganic vapor deposition of (Ba,Sr)TiO3/Ru/Ti(ON) capacitor stacks

We investigate the failure mechanism of a Pt/BST/Ru/Ti(ON)/TiSi2 capacitor structure prepared at temperatures from room temperature to 650 .deg. C in an O2 ambient. From the X-ray diffraction and the Auger electron spectroscopy analyses, the Ti(ON) diffusion barriers are shown to be completely oxidized to the Rutile phase with the resulting structural collapse during the deposition process for the BST films at 650 .deg. C in an O2 ambient. The volume expansion of the TiO2 layer gives rise to peel-off of the capacitor stack atop the Ru layer and promotes Ru-silicidation by interdiffusion between the Ru and the poly-Si layer through the collapsed TiO2.