Abstract
In the deposition chamber of a double-tubed coaxial-line type microwave plasma chemical vapor deposition system, internal plasma parameters are measured with varying the area of the substrate table to which DC bias voltage is applied in an Ar/SiH4 plasma. It is clarified that the dependence of plasma space potential on DC bias voltage varies with varying the area of the substrate table only within a range of positive DC bias voltage. Namely, it is clarifled that sheath voltage varies with varying the area of the substrate table within the range of positive DC bias voltage. In addition, we fabricate hydrogenated amorphous silicon films with varying the area of the substrate table within the range of positive DC bias voltage and measure the deposition rate and the hydrogen concentration of films. We find that the dependence of the properties of films on DC bias voltage varies with varying the area of the substrate table. We find that the dependence of the properties of films on sheath voltage doesn't vary with varying the area of the substrate table. Therefore, it is clarified that one has to investigate the influence of positive DC bias voltage on the properties of films on the basis of sheath voltage insted of DC bias voltage.
