Method for depositing a group IV semiconductor and related semiconductor device structures
A method for depositing a Group IV semiconductor is disclosed. The method may include, providing a substrate within a reaction chamber and heating the substrate to a deposition temperature. The methods may further include, exposing the substrate to at least one Group IV precursor and exposing the substrate to at least one Group IIIA metalorganic dopant precursor. The methods may further include depositing a Group IV semiconductor on a surface of the substrate. Semiconductor device structures including a Group IV semiconductor deposited by the methods of the disclosure are also provided.
1. A method of depositing a Group IV semiconductor on a surface of a substrate comprising:
providing a substrate within a reaction chamber;
heating the substrate to a deposition temperature;
exposing the substrate to a Group IV precursor and an etchant gas to form an undoped germanium semiconductor layer, wherein the substrate is exposed to the at least one Group IV precursor and the etchant gas simultaneously and wherein the Group IV precursor consists of a single Group IV precursor selected from the group consisting of: germane (GeH 4 ), digermane (Ge 2 H 6 ), and trigermane (Ge 3 H 8 );
after forming the undoped germanium semiconductor layer by completing the exposing the substrate step, exposing the undoped germanium semiconductor layer to at least one Group IIIA metalorganic dopant precursor selected from the group consisting of: triethylindium (TEI), Di-isopropylmethylindium (DIPMeIn), Ethyldimethylindium (EDMIn), trimethylaluminum (TMA), triethylaluminum (TEA), trimethylgallium (TMG) and triethylgallium (TEG), whereby flow of the at least one Group IV precursor and at least one Group IIIA metalorganic dopant precursor are separated; and
redistributing p-type dopants from the at least one Group IIIA metalorganic dopant precursor throughout the undoped germanium semiconductor layer, thereby forming a doped germanium semiconductor layer.
2. The method of claim 1 , wherein depositing the undoped germanium semiconductor layer on the surface of the substrate further comprises, selectively depositing the undoped germanium semiconductor layer on a monocrystalline surface of the substrate and subsequently exposing the undoped germanium semiconductor layer to the at least one Group IIIA metalorganic dopant precursor.
3. The method of claim 2 , wherein exposing the undoped germanium semiconductor layer to the at least one Group IIIA metalorganic dopant precursor further comprises exposing the undoped germanium semiconductor layer to the at least one Group IIIA metalorganic dopant precursor until an exposed surface of the undoped germanium semiconductor layer is saturated with the at least one Group IIIA metalorganic dopant precursor.
4. The method of claim 2 , wherein exposing the undoped germanium semiconductor layer to the at least one Group IIIA metalorganic dopant precursor further comprises heating the substrate to a temperature of between approximately 280° C. and approximately 700° C.
5. The method of claim 2 , wherein selectively depositing an undoped germanium semiconductor layer and subsequently exposing the undoped germanium semiconductor layer to the at least one Group IIIA metalorganic dopant precursor is repeated one or more times.
6. The method of claim 2 , wherein selectively depositing the undoped germanium semiconductor layer on the monocrystalline surface of the semiconductor further comprises depositing the undoped germanium semiconductor to a thickness of between approximately 10 Angstroms and approximately 25 Angstroms.
7. The method of claim 1 , further comprising selecting the etchant gas to comprise chlorine (Cl 2 ).
8. The method of claim 1 , wherein depositing the undoped germanium semiconductor layer on the surface of the substrate further comprises: depositing a monocrystalline germanium semiconductor on one or more monocrystalline surfaces of the substrate.
9. The method of claim 1 , wherein heating the substrate to a deposition temperature further comprises heating the substrate to a temperature between approximately 280° C. and approximately 700° C.
10. The method of claim 1 , wherein forming a doped germanium semiconductor layer comprises depositing the Group IV semiconductor with a doping concentration of greater than approximately 1×10 20 carriers per cubic centimeter.
11. The method of claim 1 , wherein exposing the substrate to at least one Group IIIA metalorganic dopant precursor further comprises incorporating carbon into the deposited germanium semiconductor layer, the atomic percentage of carbon in the Group IV semiconductor being greater than approximately 0.5 at-%.
12. A semiconductor device structure comprising the germanium semiconductor deposited according to the method of claim 1 .
13. The semiconductor device structure of claim 12 , wherein the germanium semiconductor comprises a p-type stressor region.
14. The semiconductor device structure of claim 13 , further comprising forming an electrical contact to the p-type stressor region, wherein the electrical contact has an electrical resistivity of less than 1×10 −8 Ohm·cm 2 .
15. The method of claim 1 , further comprising heating the substrate to a temperature of between approximately 600° C. and approximately 700° C. after exposing the substrate to the at least one Group IIIA metalorganic dopant precursor.
16. The method of claim 1 , wherein the undoped germanium semiconductor layer is substantially free of carbon.
17. A method of depositing a Group IV semiconductor on a surface of a substrate comprising:
providing a substrate within a reaction chamber;
heating the substrate to a deposition temperature;
exposing the substrate to a single Group IV precursor and an etchant gas to form an undoped germanium semiconductor layer, wherein the substrate is exposed to the single Group IV precursor and the etchant gas simultaneously and wherein the undoped germanium semiconductor layer is formed solely by performing the exposing the substrate to the single Group IV precursor and the etchant gas and wherein the Group IV precursor consists of a single Group IV precursor selected from the group consisting of: germane (GeH 4 ), digermane (Ge 2 H 6 ), and trigermane (Ge 3 H 8 );
after forming the undoped germanium semiconductor layer by completing the exposing the substrate step, exposing the undoped germanium semiconductor layer to at least one Group IIIA metalorganic dopant precursor selected from the group consisting of: triethylindium (TEI), Di-isopropylmethylindium (DIPMeIn), Ethyldimethylindium (EDMIn), trimethylaluminum (TMA), triethylaluminum (TEA), trimethylgallium (TMG) and triethylgallium (TEG), whereby flow of the at least one Group IV precursor and at least one Group IIIA metalorganic dopant precursor are separated,
redistributing p-type dopants from the at least one Group IIIA metalorganic dopant precursor throughout the undoped germanium semiconductor layer, thereby forming a doped germanium semiconductor layer.