Abstract: The manufacture of VLSI devices is facilitated by a method for chlorine reactive sputter etching of silicon materials in a plasma reactor that has been passivated by a previous etching operation involving a fluorine-containing gas. The passivated reactor is reactivated for chlorine reactive sputter etching by the generation of a boron trichloride plasma in the reactor. In the preferred embodiment, a mixture of boron trichloride and chlorine is used to initiate the etching of the silicon material before pure chlorine is used to complete the etch. The invention permits silicon materials to be etched in a reactor in which chlorine and fluorine-containing gases are used sequentially.