Kinetics and mechanisms of TiN oxidation beneath Pt thin films

Abstract

Oxidation kinetics are reported for TiN thin film diffusion barriers beneath polycrystalline Pt films of 50-200 nm thickness annealed in dry O 2 /N 2 ambients of varying oxygen partial pressure and total pressure near 1 atm. Oxygen resonance backscattering spectrometry was used to detect thin oxide layers at the Pt/TiN interface produced by oxidation annealing at 475-650°C. Over part of this temperature range, a linear oxidation rate law was observed for the buried TiN film, indicating the oxidation rate was independent of average titanium oxide thickness. Possible rate-controlling oxidation mechanisms are analyzed critically in light of the kinetic data and results from microstructural studies of the Pt/TiN specimens. We conclude that the rate-limiting step in the Pt/TiN oxidation process is diffusion of oxygen through the Pt grain boundaries.

Stability of thin platinum films implemented in high-temperature microdevices

“…Our results for the Pt thin films with Ti adhesion layer are very consistent with results from literature [18,[36][37][38][39][40][41][42][43]. Both XRD and AES measurements showed evidence of oxidation of the Ti adhesion layer after annealing, which is enhanced in O 2 -rich environments, where in the AES depth profiles it was also observed that Ti had diffused through the Pt film to form an oxide either embedded in or on top of the Pt film.…”

(Ba,Sr)TiO3 dielectrics for future stacked- capacitor DRAM

“…In the simple stacked-capacitor structure, the side of the barrier is directly exposed to the oxygen processing ambient, whereas in structures with a recessed barrier [5] or where the side of the barrier is covered with an insulating or noble-metal [6] layer, the barrier is primarily exposed to oxygen diffusing through the electrode grain boundaries [7]. In the simple stacked-capacitor structure, the side of the barrier is directly exposed to the oxygen processing ambient, whereas in structures with a recessed barrier [5] or where the side of the barrier is covered with an insulating or noble-metal [6] layer, the barrier is primarily exposed to oxygen diffusing through the electrode grain boundaries [7].…”

Characteristics of sputtered Ti1−xAlxN films for storage node electrode barriers

“…Since these high-permittivity ͑k͒ dielectrics are generally prepared in an oxidizing ambient at elevated process temperatures of above 450°C and require an additional improvement anneal after the high-k deposition and patterning process, [9][10][11][12][13][14] use of conventional sputtered TiN is no longer stable against oxidant diffusing through the Pt electrode. Since these high-permittivity ͑k͒ dielectrics are generally prepared in an oxidizing ambient at elevated process temperatures of above 450°C and require an additional improvement anneal after the high-k deposition and patterning process, [9][10][11][12][13][14] use of conventional sputtered TiN is no longer stable against oxidant diffusing through the Pt electrode.…”