Conducting diffusion barrier layers play a critical role in high-density memory integration. We recently demonstrated that Ti–Al can be used as a diffusion barrier layer for the integration of ferroelectric capacitors with complementary metal–oxide semiconductor devices for the fabrication of nonvolatile ferroelectric random access memories (NVFRAMs). Here, we discuss results from systematic studies designed to understand Ti–Al film growth and oxidation processes using in situ ion beam sputter deposition in conjunction with complementary in situ atomic layer-resolution mass spectroscopy of recoil ion (MSRI) and surface sensitive x-ray photoelectron spectroscopy (XPS). The concurrent MSRI/XPS analysis revealed that amorphous Ti–Al layers produced by tailored sputter-deposition methods are resistant to oxidation to at least 600 °C, and that oxidation occurs only when the a-Ti–Al layers are exposed to oxygen at >600 °C, via the segregation of Ti species to the surface and TiO2 formation. The a-Ti–Al layers discussed in this letter could be used in the double functionality of a bottom electrode/diffusion barrier for the integration of ferroelectric capacitors with Si substrates for the fabrication of NVFRAMs and other devices.