A method for isotropically etching film on a substrate with atomic layer control includes a) providing a substrate including a material selected from a group consisting of silicon (Si), germanium (Ge) and silicon germanium (SiGe). The method includes b) depositing a sacrificial layer on the material in a processing chamber by: cooling a lower portion of the substrate; one of creating or supplying an oxidant-containing plasma in the processing chamber; and increasing a surface temperature of the substrate for a predetermined period using rapid thermal heating while creating or supplying the oxidant-containing plasma in the processing chamber. The method includes c) purging the processing chamber. The method includes d) etching the sacrificial layer and the material by supplying an etch gas mixture and striking plasma in the processing chamber.