A method for operating a plasma reactor to etch high-aspect-ratio features on a workpiece in a vacuum chamber. The method comprises the performance of an etch process followed by a flash process. During the etch process, a first gas is supplied into the vacuum chamber, and a plasma of the first gas is maintained for a first period of time. The plasma of the first gas comprises etchant and passivant species. During the flash process, a second gas comprising a deposit removal gas is supplied into the vacuum chamber, and a plasma of the second gas is maintained for a second period of time. The DC voltage between the workpiece and the plasma of the second gas during the second period of time is significantly less than the DC voltage between the workpiece and the plasma of the first gas during the first period of time.