Aluminum-catalyzed epitaxial growth of silicon nanowire (SiNW) arrays was performed on Si wafer by chemical vapor deposition at 600°C using silane diluted in hydrogen. The effect of silane partial pressure on the SiNW morphology was studied. At high silane partial pressure, the surface is rough with a thick amorphous coating whereas at low silane partial pressure the surface is smooth. The arrays showed a low optical total reflectance in the visible light spectrum, with a minimum of 2% around 450 nm wavelength. Following SiNW growth, dry etching of the Al catalyst was performed in situ using HCl chemistry at 600°C. The effectiveness of aluminum etching was assessed by energy dispersive X-ray spectroscopy and by a controlled growth experiment. This SiNW array growth and subsequent catalyst dry etching opens up the possibility of an all in vacuum fabrication process of radial junction solar cells.