Ta-O (Ta-oxide) and Nb-O (Nb-oxide) Film Deposition Using an Electron Cyclotron Resonance Plasma

The low temperature depositions (under 200°C) of Ta-O and Nb-O films are investigated using microwave ECR (electron cyclotron resonance) plasma deposition with Ta-halide or Nb-halide and O 2 as raw material gases. High deposition rate (400 Å/min) is easily obtained with Ta-chloride and Nb-chloride, however, with Ta-fluoride and Nb-fluoride the deposited films at 200 Å/min have low resistance against humidity due to their fluoride content. The refractive indices of the Ta-O and Nb-O are 2.15 and 2.2 at 6328 Å. The structures of both films are amorphous. They are stable up to 400°C.