Synthesis of VO2 Thin Films by Atomic Layer Deposition with TEMAV as Precursor

Abstract

Synthesis and growth of Vanadium dioxide on Silicon substrates has been investigated by Atomic Layer Deposition (ALD). ALD Vanadium oxide films were synthesized by using the novel Tetrakis[ethylmethylamino] vanadium {V(NEtMe)4} [TEMAV], as the vanadium precursor source and H2O vapor as the oxidizing source. The as-prepared ALD thin films were amorphous due to low temperature growth at 150 oC and exhibit a mixture of V2O5 and VO2 phases, which originiate from the V4+ and V5+ valence states of Vanadium found in the initially amorphous ALD thin film. We found that VO2 formation is strongly dependent on the amount of pressure and oxygen. The VO2 films were formed at 450 -500 oC and with an oxygen flow rate of less than 1 sccm in a vacuum of 2.7 E-2 Torr. ALD VO2 films, after furnace annealing, demonstrate well-formed roundish grains. The ALD VO2 thin films yielded an rms roughness of 3 nm by AFM analysis and are random polycrystalline after annealing.