Vanadium oxide thin films for bolometric applications deposited by reactive pulsed dc sputtering

Vanadium oxide (VOx) thin films were deposited by reactive pulse dc magnetron sputtering process using a pure vanadium metal target. The structural, microstructure, and electrical properties were correlated as a function of processing parameters such as substrate temperature, Ar:O partial pressures ratios, and pulsed dc power to fabricate these films. The VOx films deposited at various substrate temperatures between 30 and 300 degrees C using a range of oxygen to argon partial pressure ratios exhibited huge variation in their microstructure even though most of them are amorphous to x-ray diffraction technique. In addition, the electrical properties such as temperature coefficient of resistance (TCR), resistivity, and noise levels were influenced by film microstructure. The TCRs of the VOx films were in the range of -1.1% to -2.4% K-1 having resistivity values of 0.1-100 cm. In particular, films grown at lower substrate temperatures with higher oxygen partial pressures have shown finer columnar grain structure and exhibited larger TCR and resistivity.