Electrical properties of Ta2O5 films obtained by plasma enhanced chemical vapor deposition using a TaF5 source

Abstract

High quality Ta2O5 thin films have been obtained from TaF5 and O2 using a microwave excited electron cyclotron resonance plasma at low pressure (∼2 mTorr). Physical and electrical measurements reveal that the as-deposited amorphous films have excellent properties: refractive indices ∼2.16, dielectric constants ∼25, and leakage currents <10−10 A cm−2 at 2.5 V (0.3 MV cm−1, 85 nm thick, 13 nm SiO2 equivalent). Trapping and conduction properties of these layers have also been investigated, showing a reversible electron trapping and a trap-limited Poole–Frenkel effect.