flowing a silicon-containing precursor into a substrate processing region of a semiconductor processing chamber;

flowing a boron-containing precursor into the substrate processing region of the semiconductor processing chamber; and

depositing a boron-and-silicon-containing layer on a substrate in the substrate processing region of the semiconductor processing chamber, wherein the boron-and-silicon-containing layer is characterized by a linearly increasing ratio of boron-to-silicon from a first surface in contact with the substrate to a second surface of the boron-and-silicon-containing layer opposite the first surface, and wherein a flow rate of the boron-containing precursor increases non-linearly during the deposition of the boron-and-silicon-containing layer.