IMPROVED FLUORINATED HYDROGENATED AMORPHOUS-SILICON ALLOYS PREPARED USING THE HOT-PLASMA-BOX GLOW-DISCHARGE TECHNIQUE

The structural, optical and electrical properties of fluorinated hydro genated amorphous silicon alloy thin films grown from a SiF4-SiH4-H-2 gas mixture in a new hot-plasma-box (HPB) glow-discharge reactor are r eported. We observed that the HPB technique provides almost four times better growth rates (as high as 2.4 angstrom s-1) for r.f. powers as low as 200 mW cm-2 together with an order-of-magnitude improvement in the photoconductivity gain (to as high as 2 x 10(5)) compared with fil ms deposited using the conventional r.f. plasma chemical vapour deposi tion technique and the same gas mixture. Furthermore, Raman scattering measurements indicate that there is a substantial enhancement of the structural short-range order (SRO) in these alloy films prepared in th e HPB. The improvement in the optoelectronic properties of the films a nd its correlation with the improvement of SRO are discussed in this p aper.