Production of TiN thin films by N-2-laser-ablated Ti atoms in nitrogen gasatmospheres

Laser ablation has proven to be an important technique for thin film deposi tion because of the high velocity heating and quenching of materials. We ha ve used a nitrogen laser, which is capable of producing nanosecond pulses o f intense UV (337.1 nm) radiation to generate high-temperature and high-ele ctron-density plasmas when strongly focused on titanium targets. Laser beam pulses with a peak energy of 32 J/cm(2) and a power density of 1.6 GW/cm(2 ) were used in this experiment. As ablated Ti species are allowed to expand further in a nitrogen atmosphere, they cool down and eventually dissipate. In this sequence, they meet a substrate where condensation, nucleation, an d growth processes yield TiN thin films because of the reaction with the ni trogen gas. Thin film depositions were made on stainless steel (AISI 1020 a nd AISI 304) substrates at nitrogen gas pressures ranging from 10(-1) Pa to 200 Pa and for different distances between the substrate and the spot wher e the laser beam was focused upon the target. For rather short distances (l ess than 7 mm), optical microscopy shows the effect of a further plasma-thi n film interaction, while at larger distances, the depositions exhibit a re gular film condensation from the vapor. Microstructure characterization of the thin film deposited was done by several techniques. The typical cubic T iN phase was identified by transmission electron microscopy (TEM) and energ y dispersion spectroscopy (EDS).