Excimer laser reactive deposition of vanadium nitride thin films

We report on the deposition of thin vanadium nitride films by ablating vanadium targets in low-pressure N2 atmosphere, and on their characterization. The targets were vanadium foils (purity 99.8%). 3 in. Si(1 1 1) wafers were used as substrates. Film characteristics (composition and crystalline structure) were studied as a function of N2 pressure (0.5–200 Pa), KrF laser fluence (4.5–19 J/cm2), substrate temperature (20–750 °C) and target-to-substrate distance (30–70 mm). Vanadium nitride is already formed at low N2 ambient pressures (1 Pa) and laser fluences (6 J/cm2) on substrates at room temperature. At the N2 pressures of 1–10 Pa, the prevalent phase is VN. At higher pressures (100 Pa) and at relatively high laser fluences (16–19 J/cm2), the dominant phase is V2N. The crystallinity of the films improves by increasing the substrate temperature. Well-crystallized films are obtained on substrates heated at 500 °C.