Improved fluorinated hydrogenated amorphous silicon alloys prepared using the hot-plasma-box glow-discharge technique

Abstract

The structural, optical and electrical properties of fluorinated hydrogenated amorphous silicon alloy thin films grown from a SiF₄-SiH₄-H₂ gas mixture in a new hot-plasma-box (HPB) glow-discharge reactor are reported. We observed that the-HPB technique provides almost four times better growth rates (as high as 2–4 Å s⁻¹) for r.f. powers as low as 200mW cm⁻² together with an order-of-magnitude improvement in the photoconductivity gain (to as high as 2 × 10⁵) compared with films deposited using the conventional r.f. plasma chemical vapour deposition 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 the HPB. The improvement in the optoelectronic properties of the films and its correlation with the improvement of SRO are discussed in this paper.