IN-SITU AND REAL-TIME ROOM-TEMPERATURE OXIDATION STUDIES OF FCC TIN THIN-FILMS

In-situ and real time ellipsometry was used to study the oxidation pro cess of thin fee TINx films. The films were grown by DC reactive magne tron sputtering at various negative bias voltages (V-b) in order to de posit TiNx with different stoichiometries and then exposed to several gases and to air at room temperature. The oxidation rate was found to depend strongly on the V-b. High oxidation is observed at low V-b, whe re the nitrogen is weakly bonded to Ti and thus more easily can be rep laced. By analysing the spectroscopic ellipsometry (SE) data, it was f ound that oxidation takes place in the bulk of the film and can procee d up to a 10% transformation of titanium nitride into oxide. From the SE results and those obtained from stress measurements during exposure to air, it is concluded that the fastest and most important mechanism for the film oxidation is through grain boundary diffusion and reacti on of oxygen with the weakly bonded Ti-N.