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 usi ng a microwave excited electron cyclotron resonance plasma at low pres sure (similar to 2 mTorr). Physical and electrical measurements reveal that the as-deposited amorphous films have excellent properties: refr active indices similar to 2.16, dielectric constants similar to 25, an d leakage currents < 10(-10) A cm(-2) at 2.5 V (0.3 MV cm(-1), 85 nm t hick, 13 nm SiO2 equivalent). Trapping and conduction properties of th ese layers have also been investigated, showing a reversible electron trapping and a trap-limited Poole-Frenkel effect. (C) 1996 American In stitute of Physics.