Selective etching between silicon-and-germanium-containing materials with varying germanium concentrations

A semiconductor processing method comprising:

• providing an oxygen-containing precursor to a processing region of a semiconductor processing chamber, wherein a substrate is housed within the processing region, wherein a first layer of silicon-and-germanium-containing material and a second layer of silicon-and-germanium-containing material are disposed on the substrate, and wherein the first layer of silicon-and-germanium-containing material is characterized by a greater germanium concentration than the second layer of silicon-and-germanium-containing material;
• contacting the substrate with the oxygen-containing precursor, wherein the contacting at least partially oxidizes the first layer of silicon-and-germanium-containing material to a greater degree than the second layer of silicon-and-germanium-containing material;
• providing a fluorine-containing precursor to the processing region;
• and
• contacting the substrate with the fluorine-containing precursor, wherein the contacting etches the first layer of silicon-and-germanium-containing material relative to the second layer of silicon-and-germanium-containing material at a selectivity of greater than or about 40:1.

A semiconductor processing method comprising:

• providing a hydrogen-containing precursor or a nitrogen-containing precursor to a processing region of a semiconductor processing chamber, wherein a substrate is housed within the processing region, wherein a first layer of silicon-and-germanium-containing material and a second layer of silicon-and-germanium-containing material are disposed on the substrate, wherein the first layer of silicon-and-germanium-containing material is characterized by a greater germanium concentration than the second layer of silicon-and-germanium-containing material, and wherein a native oxide is present on the first layer of silicon-and-germanium-containing material and the second layer of silicon-and-germanium-containing material;
• contacting the substrate with the hydrogen-containing precursor or the nitrogen-containing precursor, wherein the contacting removes the native oxide from the first layer of silicon-and-germanium-containing material and the second layer of silicon-and-germanium-containing material;
• providing an oxygen-containing precursor to the processing region, wherein the oxygen-containing precursor comprises water or steam (H2O);
• contacting the substrate with the oxygen-containing precursor, wherein the contacting oxidizes at least a portion of the first layer of silicon-and-germanium-containing material and at least a portion the second layer of silicon-and-germanium-containing material, and wherein the processing region is maintained plasma-free while contacting the substrate with the oxygen-containing precursor;
• providing a fluorine-containing precursor to the processing region;
• and
• contacting the substrate with the fluorine-containing precursor, wherein the contacting selectively etches the first layer of silicon-and-germanium-containing material, and wherein the processing region is maintained plasma-free while contacting the substrate with the fluorine-containing precursor.