A method of forming a punch through stop region in a fin structure is disclosed. The method may include forming a doped glass layer on a fin structure and forming a masking layer on the doped glass layer. The method may further include removing a portion of the masking layer from an active portion of the fin structure, and removing an exposed portion the doped glass layer that is present on the active portion of the fin structure. A remaining portion of the doped glass layer is present on the isolation portion of the fin structure. Dopant from the doped glass layer may then be diffused into the isolation portion of the fin structure to form the punch through stop region between the active portion of the fin structure and a supporting substrate.