Contact resistance reduction by III-V Ga deficient surface
A method for forming a semiconductor device includes forming a III-V semiconductor substrate and forming a gate structure on the III-V semiconductor substrate. The method also includes forming a thin spacer surrounding the gate structure and forming a source/drain junction with a first doped III-V material at an upper surface of the III-V semiconductor substrate. The method also includes oxidizing a surface the source/drain forming an oxidation layer; removing natural oxides from the oxidation layer on a surface of the source/drain to expose ions of the first doped material at least at a surface of the source/drain. The method further includes applying a second doping to the source/drain to increase a doping concentration of the first doped III-V material, forming metal contacts at least at the second doped surface of the source/drain; and then annealing the contact.
1. A method of forming a semiconductor device, the method comprising:
forming a III-V semiconductor substrate;
forming a gate structure on the III-V semiconductor substrate;
forming a spacer surrounding the gate structure;
forming a source/drain junction with a first doped III-V material at an upper surface of the III-V semiconductor substrate;
oxidizing a surface the first doped III-V material forming an oxidation layer;
removing natural oxides from the oxidation layer on a surface of the first doped III-V material to expose ions of the first doped III-V material at least at a surface of the source/drain;
applying a second doping to the exposed ions to further increase a doping concentration of the first doped III-V material at least at a surface thereof;
forming metal contacts at least at the second doped surface of the source/drain; and
annealing the metal contacts.
2. The method according to claim 1 , further comprising forming an oxide layer on top of the source/drain.
3. The method according to claim 2 , further comprising removing a trench in the oxide layer to expose at least a portion of a surface of the first doped III-V material proximate to the oxide layer.
4. The method according to claim 2 , wherein the oxide layer is formed with SiO 2 .
5. The method according to claim 1 , wherein the oxidizing is accomplished with ozone.
6. The method according to claim 1 , wherein the removing is by HF or HCl etching.
7. The method according to claim 1 , wherein the removing is by plasma ion bombardment.
8. The method according to claim 1 , wherein the first doping is in situ.
9. The method according to claim 1 , wherein the second doping is at least one or more of plasma doping followed by annealing processing, and low temperature thermal dissociation.
10. The method according to claim 1 , wherein the doping concentration is increased by at least about 50%.
11. The method according to claim 1 , wherein the III-V semiconductor is InGaAs.
12. The method according to claim 1 wherein the nFET transistor is at least one of a planar FET, trench FET, and FINFET.
13. A method of reducing metal contact resistance in a III-V type material, the method comprising:
forming a III-V semiconductor substrate;
forming a junction with a first doped III-V material at an upper surface of the III-V semiconductor substrate;
oxidizing a surface a first doped III-V material forming an oxidation layer;
removing natural oxides from the oxidation layer on a surface of the a first doped III-V material to expose ions of the first doped III-V material;
applying a second doping to the first doped III-V material to increase a doping concentration of the first doped III-V material at least at a surface thereof and form a second doped III-V material;
forming metal contacts at least at a portion of the surface of the second doped III-V material; and
annealing the metal contacts.
14. The method according to claim 13 , wherein the oxidizing is accomplished with ozone.
15. The method according to claim 13 , wherein the removing is by HF or HCl etching.
16. The method according to claim 13 , wherein the first doping is in situ.
17. The method according to claim 13 , wherein the second doping is at least one or more of plasma doping followed by annealing processing, and low temperature thermal dissociation.
18. The method according to claim 13 , wherein the doping concentration is increased by at least about 50%.
19. The method according to claim 13 , wherein the III-V semiconductor is InGaAs.