Auger Electron Spectroscopy Study on the Stability and the Interfacial Reaction of Ta, Ta-N and TaN Films as a Diffusion Barrier between Cu₉Al₄ Film and Si

The diffusion barrier properties of Ta, Ta-N and TaN films to Si and the Cu 9 Al 4 compound have been studied by examining depth profiles obtained from Auger electron spectroscopy. The contact system degrades with the silicide formation at the interface between the barrier and the Si substrate. The silicide formation temperature of these films was 650°C for the Ta barrier and 700°C for the Ta-N one. The contact system using the TaN compound barrier tolerates a temperature of 750°C. Ta atoms are the diffusing species for silicide formation in the present study, which protects the contact system from catastrophic failure due to the intermixing of all elements at higher temperatures.