Low pressure microwave electron cyclotron resonance plasma deposition of amorphous Ta2O5 films

Abstract

Deposition of Ta2O5 from Ta(OC2H5)5 and O2 has been studied using a distributed electron cyclotron resonance plasma. Carbon contamination levels as low as 1.5% have been obtained when the Ta(OC2H5)5 vapor is introduced ‘‘downstream’’ away from the plasma volume. Electrical measurements (current density/voltage, capacitance/voltage) suggest the films have dielectric constants ∼22 and leakage currents ∼10−10 A cm−2 for 2 V operation (50 nm thick, 10 nm a-SiO2 equivalent). These values are obtained without the necessity for high temperature annealing and recrystallization. The conduction mechanism is attributed to the Poole–Frenkel effect.