Influence of argon on crystalline silicon film growth by ECR plasma CVD for solar cells

This work reports on the influence of Ar on the growth of crystalline silicon films from dilute silane-hydrogen mixtures using the technique of electron cyclotron resonance (ECR) plasma-enhanced chemical vapour deposition (PECVD). Ar addition leads to significant changes in film deposition. For example, a significant decrease in the deposition rate with increasing Ar content is observed. Argon is also effective in suppressing the hydrogen content in amorphous Si films deposited at low temperatures. Importantly, Ar addition has enabled us to prepare intrinsic microcrystalline silicon films with improved light to dark conductivity ratios of up to /spl sim/500. These layers have been used in simple p-i-n solar cell structures deposited on p-type Si wafers. An efficiency of 9.5% and an open circuit voltage of 560 mV have been observed using 1 /spl mu/m thick i-layers.