Production of VHF excited H2 Plasma by New Method of Superposing the Standing Waves

A novel VHF plasma source using a method of superposing standing waves is proposed in this article. The characteristics of VHF plasma generated by this method were measured with the Langmuir probe and a digital camera. Here, the frequency was 80 MHz, and an electrode size and discharge gap of electrodes was 1 800 × 300 mm2 and 20 mm, respectively. The distributions of plasma light emission were uniform across the whole electrode in the pressure range from 0.1 to 0.3 Torr. The spatial profile of the ion saturation current density was flat in the direction of the electrode. In this case, the non-uniformity of VHF plasma was less than ±10% at 0.3 Torr.