Electrical modelling of RF coupled inductors supplying a double frequency inductive plasma reactor

Abstract

A new inductive plasma reactor has been developed for thin-film depositions using the plasma enhanced chemical vapour deposition (PECVD) process. This apparatus combines an inductive plasma generation at 13.56 MHz, plus a direct heating of the substrate by a supplementary inductive set-up at 100 kHz. The unavoidable coupling of the two coaxial coils allows one electrical generator to force power in the other, compromising the reliability of the system, unless rejecting filters are inserted. Therefore, an equivalent circuit of the double-coil set is needed to specify and design the necessary filters. The aim of this paper is to present and justify the electrical representation of this very special, high-frequency transformer which has been used successfully.