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

High quality Ta2O5 thin films have been obtained from TaF5 and O-2 using a microwave excited electron cyclotron resonance plasma at low pressure (similar to 2 mTorr). Physical and electrical measurements reveal that the as-deposited amorphous films have excellent properties: refractive indices similar to 2.16, dielectric constants similar to 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. (C) 1996 American Institute of Physics.