The synthesis of silicon nanowires (SiNWs) is carried out at 250 °C under pure hydrogen plasma from monocrsytalline silicon substrates or amorphous silicon thin film, using indium as a catalyst. Studies have been carried out in function of the duration of the hydrogen plasma. The results showed a growth of smooth surface nanowire arrays (diameter 100 nm, length 500 nm) from an indium thickness of 20 nm and a hydrogen plasma duration of 30 min. The growth of nanowires for longer hydrogen plasma durations has led to SiNWs with larger diameters and rougher surfaces, revealing the onset of secondary nanowire growth on these surfaces, probably due to the presence of indium residues. The results present a new procedure for the 3D solid liquid solid growth mode of SiNWs.