Tantalum oxide and nitride spectral features from a laser-produced plasma

We report measurements of time-resolved Ta, TaO and TaN emission spectroscopic signatures from a laser-produced plasma. Plasmas were generated using 1064 nm, 6 ns pulses from an Nd:YAG laser focused onto a pure Ta metal target in a gaseous environment with varying percentages of O₂/N₂ for controlling gas-phase oxidation/plasma chemistry. Time-resolved analysis showed that Ta oxide emission is prominent at later times in plasma evolution, whereas strong atomic emission is present at early times in air. Emission spectral features as a function of O₂ partial pressure showed that TaO emission intensity increases, while the peak intensity of TaO appears earlier with increasing O₂ availability. We also report emission spectra of TaN, and show that plasma chemistry favors TaO formation instead of TaN when O₂ is present in the environment.