Selective etching of silicon-and-germanium-containing materials with increased surface purities
Exemplary semiconductor processing methods may include providing an oxygen-containing precursor to a processing region of a semiconductor processing chamber. A substrate may be housed within the processing region. A first layer of silicon-and-germanium-containing material, a second layer of silicon-and-germanium-containing material, and a layer of silicon-containing material may be disposed on the substrate. The methods may include contacting the substrate with the oxygen-containing precursor. The contacting may oxidize at least a portion of the second layer of silicon-and-germanium-containing material. The methods may include providing a first etchant precursor to the processing region and contacting the substrate with the first etchant precursor. The contacting may selectively etch the first layer of silicon-and-germanium-containing material. The methods may include providing a second etchant precursor to the processing region. The methods may include contacting the substrate with the second etchant precursor. The contacting may etch a portion of the layer of silicon-containing material.
1. An 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, and wherein a first layer of silicon-and-germanium-containing material, a second layer of silicon-and-germanium-containing material, and a layer of silicon-containing material are disposed on the substrate;
contacting the substrate with the oxygen-containing precursor, wherein the contacting oxidizes at least a portion of the second layer of silicon-and-germanium-containing material;
providing a first etchant precursor to the processing region;
contacting the substrate with the first etchant precursor, wherein the contacting selectively etches the first layer of silicon-and-germanium-containing material;
providing a second etchant precursor to the processing region; and
contacting the substrate with the second etchant precursor, wherein the contacting etches a portion of the layer of silicon-containing material.
2. The semiconductor processing method of claim 1 , wherein:
the first layer of silicon-and-germanium-containing material is characterized by a first germanium concentration;
the second layer of silicon-and-germanium-containing material is characterized by a second germanium concentration; and
the first germanium concentration is less than the second germanium concentration.
3. The semiconductor processing method of claim 1 , wherein the oxygen-containing precursor comprises diatomic oxygen (O 2 ) or steam (H 2 O).
4. The semiconductor processing method of claim 1 , further comprising:
forming plasma effluents of the oxygen-containing precursor.
5. The semiconductor processing method of claim 1 , wherein the second etchant precursor comprises a fluorine-containing precursor.
6. The semiconductor processing method of claim 1 , further comprising:
providing a hydrogen-containing precursor with the second etchant precursor.
7. The semiconductor processing method of claim 1 , wherein the portion of the layer of silicon-containing material is characterized by a thickness of less than or about 7 nm.
8. The semiconductor processing method of claim 1 , wherein a pressure in the processing region is maintained at less than or about 30 Torr.
9. The semiconductor processing method of claim 1 , wherein the contacting with the first etchant precursor 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.
10. The semiconductor processing method of claim 1 , wherein a temperature in the processing region is maintained at greater than or about 150° C.
11. The semiconductor processing method of claim 1 , wherein contacting the substrate with the oxygen-containing precursor, contacting the substrate with the first etchant precursor, and contacting the substrate with the second etchant precursor is performed on a single mainframe.
12. 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, a second layer of silicon-and-germanium-containing material, and a layer of silicon-containing material are disposed on the substrate, and wherein the first layer of silicon-and-germanium-containing material is characterized by a lesser germanium concentration than the second layer of silicon-and-germanium-containing material;
contacting the substrate with the oxygen-containing precursor, wherein the contacting oxidizes at least a portion of the second layer of silicon-and-germanium-containing material;
providing a first fluorine-containing precursor to the processing region;
contacting the substrate with the first 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;
providing a second fluorine-containing precursor to the processing region;
forming plasma effluents of the second fluorine-containing precursor; and
contacting the substrate with the second fluorine-containing precursor, wherein the contacting etches between about 2 nm and about 5 nm of the layer of silicon-containing material.
13. The semiconductor processing method of claim 12 , wherein the first layer of silicon-and-germanium-containing material is characterized by a germanium concentration of less than or about 35 at. %.
14. The semiconductor processing method of claim 12 , wherein the second layer of silicon-and-germanium-containing material comprises a doped silicon-and-germanium-containing material.
15. The semiconductor processing method of claim 12 , wherein the oxygen-containing precursor comprises diatomic oxygen (O 2 ) or steam (H 2 O).
16. The semiconductor processing method of claim 15 , further comprising:
forming plasma effluents of H 2 O.
17. The semiconductor processing method of claim 12 , wherein, subsequent contacting the substrate with the second fluorine-containing precursor, a surface of the layer of silicon-containing material is characterized by a germanium concentration of less than or about 1.5 at. %.
18. A semiconductor processing method comprising:
providing an oxygen-containing precursor to a processing region of a semiconductor processing chamber, wherein the oxygen-containing precursor comprises diatomic oxygen (O 2 ) or steam (H 2 O), wherein a substrate is housed within the processing region, wherein a first layer of silicon-and-germanium-containing material, a second layer of silicon-and-germanium-containing material, and a layer of silicon-containing material are disposed on the substrate, and wherein the first layer of silicon-and-germanium-containing material is characterized by a lesser germanium concentration than the second layer of silicon-and-germanium-containing material;
contacting the substrate with the oxygen-containing precursor, wherein the contacting oxidizes at least a portion of the second layer of silicon-and-germanium-containing material;
providing a first fluorine-containing precursor to the processing region;
contacting the substrate with the first fluorine-containing precursor, wherein the contacting selectively etches the first layer of silicon-and-germanium-containing material;
providing a second fluorine-containing precursor and a hydrogen-containing precursor to the processing region;
forming plasma effluents of the second fluorine-containing precursor and the hydrogen-containing precursor; and
contacting the substrate with the plasma effluents of the second fluorine-containing precursor and the hydrogen-containing precursor, wherein the contacting etches between about 2 nm and about 5 nm of the layer of silicon-containing material.
19. The semiconductor processing method of claim 18 , wherein a temperature in the processing region is maintained at greater than or about 200° C.
20. The semiconductor processing method of claim 18 , wherein, subsequent contacting the substrate with the second fluorine-containing precursor, a surface of the layer of silicon-containing material is characterized by a germanium concentration of less than or about 1.0 at. %.