Selective growth of vanadium dioxide on patterned Al/SiO2 substrates by metal–organic chemical vapor deposition

Abstract

The area-selective growth of vanadium dioxide can provide a valuable self-aligned process promising for novel oxide electronics compatible with silicon technology. In the present paper, vanadium dioxide films were grown by metal–organic chemical vapor deposition on micrometer-scale patterned Al/SiO₂ substrates. The synthesis conditions, such as substrate temperature and precursor concentration in the reaction zone, were varied to achieve area-selective growth control. The results show that as the synthesis temperature increases and the precursor concentration in the gas phase decreases, the surface concentration of VO₂ crystallite nuclei on the SiO₂ surface decreases until the nucleation process ceases completely. At the same time, the VO₂ film continues to grow on the aluminum surface. The growth rate dependence on the precursor concentration in the gas phase, on the growth temperature and on the growth time is investigated. A detailed analysis using scanning electron microscopy, energy-dispersive X-ray spectroscopy and atomic force microscopy allowed us to construct a qualitative model of selective synthesis of VO₂ based on the differences in the nucleation kinetics on different substrate surfaces. From the results of X-ray diffraction analysis and temperature resistivity measurements, it is shown that the quality of the obtained films depends on the synthesis temperature and, practically, does not depend on the precursor concentration in the gas phase. The obtained results provide a better understanding of the area-selective VO₂ structure growth and can be applied in oxide electronics compatible with modern complementary metal-oxide-semiconductor processes.