Semiconductor-metal transition in thin VO2 films grown by ozone based atomic layer deposition

Thin films of vanadium dioxide (VO2) have been grown by a low temperature atomic layer deposition process at 150 °C using tetrakis[ethylmethylamino]vanadium as a vanadium source and ozone as reactant gas. Films deposited on SiO2 were amorphous, but during a thermal treatment at 450 °C tetragonal VO2(R) was formed. During in situ x-ray diffraction measurements, the semiconductor–metal transition was observed as a reversible transition between VO2(M1) and VO2(R) near 67 °C. Correlated with this phase change, a reversible change in resistivity was observed of more than two orders of magnitude for a film of 42 nm thickness.