Exemplary etching methods may include flowing a hydrogen-containing precursor into a semiconductor processing chamber. The methods may include flowing a fluorine-containing precursor into a remote plasma region of the semiconductor processing chamber. The methods may include forming a plasma of the fluorine-containing precursor in the remote plasma region. The methods may include etching a pre-determined amount of a silicon-containing material from a substrate in a processing region of the semiconductor processing chamber. The methods may include measuring a radical density within the remote plasma region during the etching. The methods may also include halting the flow of the hydrogen-containing precursor into the semiconductor processing chamber when the radical density measured over time correlates to a produced amount of etchant to remove the pre-determined amount of the silicon-containing material.