| Research Abstract |
As is well known, Radio-frequency (RF) plasmas are currently used in material processing in electronics industry, for example, in deposition and etching on thin solid substrates. The scale-up of the plasma production, such as large area/volume plasmas, has recently been desired as one of the semiconductor tecnologies. The aim of the scale-up studies is generally considered to be achivement of the time and cost reductions in device fabrication by the mass production. In particular, the development of low-cost mass production technique for fabricating amorphous silicon solar cells by means of large-area RF glow discharge is in demand.
In the light of the foregoing, the objective of this research project is to achieve the large-area RF plasma production using a surface wave. The surface wave can propagate at the plasma-dielectric interfaces along a large-area rectangular dielectric tube. The plasma is called here a "surface wave-produced plasma (SWP)". The present planar SWP theory is obtained by expanding a theory for stand ard SWP in a cylinder glass tube.
The experiments were carried out using two large-area rectangular tubes. The one is with 1.72m in length x 73cm in width x 2.5cm in height, and the other with 1m in length x 16cm in width x 2.5cm in height, respectively. In both cases the plasma was excited by a pair strip lines wound around the tube at the tube end. The large-area plasma could be produced by the even surface mode over the whole of the tubes when sufficient RF power in 13.56 and 28 MHz is put into the plasma in gas pressure 10-40mTorr. The plasma density became almost uniform, except near the side dielectric-walls and near a node of standing surface waves.
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