Effect of nitrogen gas on preparation of Ti-Al-N thin films by pulsed laser ablation

The effect of ambient N(2) gas on the preparation of Ti(0.9)Al(0.1)N (TAN) thin films for ferroelectric capacitors by pulsed laser ablation (PLA) using ArF and KrF excimer lasers was explored. The TAN films were prepared on (100)Si substrates heated at 620 degrees C in various N(2) pressures ranging from vacuum to 130 Pa. The TAN crystal growth was found to be influenced by the content of unintentionally incorporated O which was found to be controlled by the introduction of N, gas into the: deposition chamber. The O content far films prepared by KrF was found to be smaller than that for films prepared by ArF. This was due to the smaller optical absorption cross-section of KrF excimer laser for residual O(2) or H(2)O molecules in the chamber and/or the higher deposition rate. The TAN film prepared by KrF excimer laser was found to be nearly epitaxial Si with a cube-on-cube crystallographic orientation. (C) 1998 Elsevier Science B.V.