Comparative study of the effects of phosphorus and boron doping in vapor–liquid–solid growth with fixed flow of silicon gas.

This work was carried out to investigate the comparative effects of phosphorus and boron doing in vapor–liquid–solid (VLS) growth. Doped Si microneedles were grown by VLS mechanism at the temperature of 700 °C or less using Au as the catalyst. VLS growth using in-situ doping with the mixed gas of Si 2 H 6 and PH 3 produced phosphorus doped n-Si microneedles at Au dot sites, whereas, the mixed gas of Si 2 H 6 and B 2 H 6 produced boron doped p-Si microneedles. The variation of growth rate, diameter, resistivity, impurity concentration and carrier (electron, hole) mobility of these n-Si and p-Si microneeedles were investigated and compared with the variation of dopant gas (PH 3 or B 2 H 6 ) flow, with a fixed flow of Si gas (Si 2 H 6 ). This comparative study shall be helpful while fabricating devices by growing n-Si and p-Si microneedles one above another by multistep (2-step or 3-step) VLS growth. [ABSTRACT FROM AUTHOR]