Diagnostics of microwave ECR generated plasma: Effect of contaminated reference electrode

Langmuir probe diagnostics is performed on microwave ECR generated plasma that is routinely being used in our laboratory for plasma assisted chemical vapour deposition (CVD) and metal organic chemical vapour deposition (MOCVD) applications. Diagnostics is performed on Argon plasma when the plasma generation chamber was new and also after the prolonged use of this chamber for plasma assisted CVD applications. Clear differences in the values of plasma parameters from the two cases were observed and these differences are explained. The investigations reported here clearly indicate the important role of reference electrode in plasma diagnostics experiments and also suggest that it is very important to have the proper (uncontaminated) reference electrode during plasma diagnostics particularly when measurements are performed in the contaminated chamber.