Pre-clean of silicon germanium for pre-metal contact at source and drain and pre-high K at channel
The present disclosure generally relates to methods for removing contaminants and native oxides from substrate surfaces. The method includes exposing a surface of the substrate to first hydrogen radical species, wherein the substrate is silicon germanium having a concentration of germanium above about 30%, then exposing the surface of the substrate to a plasma formed from a fluorine-containing precursor and a hydrogen-containing precursor, and then exposing the surface of the substrate to second hydrogen radical species.
1. A method for processing a substrate, comprising:
exposing a surface of the substrate to hydrogen radical species;
exposing the surface of the substrate to a plasma formed from a first fluorine-containing precursor and a first hydrogen-containing precursor;
annealing the substrate;
forming an epitaxial layer on the surface of the substrate; and
between annealing the substrate and forming an epitaxial layer on the surface of the substrate, exposing the surface of the substrate to a plasma formed from a second fluorine-containing precursor and a second hydrogen-containing precursor in a first processing chamber.
2. The method of claim 1 , wherein the substrate is silicon germanium having a concentration of germanium in silicon above about 30%.
3. The method of claim 1 , wherein the hydrogen radical species are formed by exposing a hydrogen-containing gas to a hot wire chemical vapor deposition (HWCVD) source.
4. The method of claim 1 , wherein the hydrogen radical species are formed by exposing a hydrogen-containing gas to a UV light.
5. The method of claim 1 , wherein exposing the surface of the substrate to hydrogen radical species is performed in a first processing chamber.
6. The method of claim 5 , wherein the hydrogen radical species are formed in a remote plasma source separated from the first processing chamber.
7. The method of claim 5 , wherein exposing a surface of the substrate to a plasma formed from a first fluorine-containing precursor and a first hydrogen-containing precursor is performed in the first processing chamber.
8. The method of claim 7 , wherein exposing the surface of the substrate to a plasma formed from a first fluorine-containing precursor and a first hydrogen-containing precursor is performed in a second processing chamber.
9. The method of claim 8 , wherein forming an epitaxial layer on the surface of the substrate in performed in a third processing chamber.
10. The method of claim 9 , wherein the substrate is transferred between the first, second, and third processing chambers within one processing system without breaking vacuum.
11. The method of claim 1 , wherein the substrate comprises doped silicon, undoped silicon, polysilicon, crystalline silicon, silicon oxide, strained silicon, silicon germanium, doped polysilicon, germanium, sapphire (Al 2 O 3 ), silicon carbide (SiC), spinel, zinc oxide, gallium-arsenide (GaAs), lithium gallate, indium phosphide (InP), single-crystal GaN, aluminum nitride (AlN), GdScO 3 (GSO), MoSe 2 , Ge 2 Sb 2 Te 5 (GST), or combinations thereof.
12. The method of claim 1 , wherein the first and second fluorine-containing precursors comprise nitrogen trifluoride (NF 3 ), hydrogen fluoride (HF), diatomic fluorine (F 2 ), monatomic fluorine (F) and fluorine-substituted hydrocarbons, or combinations thereof.
13. A method for processing a substrate, comprising:
exposing a surface of the substrate to a plurality of plasma treatments, wherein one or more of the plasma treatments comprise exposing the surface of the substrate to a plasma formed from a fluorine-containing precursor and a hydrogen-containing precursor;
exposing the surface of the substrate to hydrogen radical species between at least two of the plurality of plasma treatments;
and then
forming an epitaxial layer on the surface of the substrate.
14. The method of claim 13 , further comprising
annealing the substrate between plasma treatments.
15. The method of claim 13 , wherein the substrate is silicon germanium having a concentration of germanium in silicon above about 30%.
16. The method of claim 13 , wherein the hydrogen radical species are formed by exposing a hydrogen-containing gas to a hot wire chemical vapor deposition (HWCVD) source.
17. The method of claim 13 , wherein the hydrogen radical species are formed by exposing a hydrogen-containing gas to a UV light.
18. A method for processing a substrate, comprising:
performing a plurality of contaminant removal processes on a surface of a substrate, wherein each contaminant removal process comprises exposing the surface of the substrate to plasma formed radical species of a fluorine-containing precursor and a hydrogen-containing precursor;
between contaminant removal processes, treating the surface of the substrate with a pre-treatment process comprising exposing a surface of the substrate to hydrogen radical species; and then
forming an epitaxial layer on the surface of the substrate.
19. The method of claim 18 , wherein the substrate is silicon germanium having a concentration of germanium in silicon above about 30%.