Methods of etching include cycles of low temperature etching of a material layer disposed on a substrate, with at least one of the cycles being followed by activation of unreacted etchant deposits during an inert gas plasma treatment. In some embodiments, a method includes: positioning a substrate in a processing chamber; generating, in a first etching cycle, a plasma from a gas mixture within the processing chamber to form a processing gas including an etchant; exposing, to the etchant, a portion of a material layer disposed on a substrate maintained at a first temperature; generating an inert gas plasma within the processing chamber; generating, in a second etching cycle, a plasma from a gas mixture within the processing chamber to form a processing gas including an etchant; and heating the substrate to a second temperature to sublimate a byproduct of reaction between the etchant and the material layer.