Laser spike annealing for solid phase epitaxy and low contact resistance in an SRAM with a shared PFET and NFET trench
Embodiments are directed to a method of forming a semiconductor device and resulting structures having a shared SRAM trench and a common contact having a low contact resistance. The method includes forming a first semiconductor fin opposite a surface of a substrate and forming a second semiconductor fin opposite the surface of the substrate and adjacent to the first semiconductor fin. A doped region is formed over portions of each of the first and second semiconductor fins and a dielectric layer is formed over the doped regions. A shared trench is formed in the dielectric layer exposing portions of the doped regions. The exposed doped regions are then amorphized and recrystallized.
1. A method for fabricating a semiconductor device, the method comprising:
forming a first semiconductor fin opposite a surface of a substrate;
forming a second semiconductor fin opposite the surface of the substrate and adjacent to the first semiconductor fin;
prior to forming a replacement metal gate (RMG), forming a first doped region over portions of the first semiconductor fin and a second doped region over portions of the second semiconductor fin;
forming a dielectric layer over the first and second doped regions;
after forming the RMG, forming a shared trench in the dielectric layer exposing portions of the first and second doped regions;
concurrently amorphizing the exposed first and second doped regions; and
concurrently recrystallizing the amorphized first and second doped regions.
2. The method of claim 1 , wherein the first semiconductor fin comprises n-type dopants and the second semiconductor fin comprises p-type dopants.
3. The method of claim 2 , wherein the n-type dopants are selected from the group consisting of As, P, and Sb.
4. The method of claim 2 , wherein the p-type dopants are selected from the group consisting of B, BF 2 , Al, and Ga.
5. The method of claim 1 , wherein forming the first doped region over portions of the first semiconductor fin further comprises:
forming a first epitaxy region over the first semiconductor fin; and
doping the first epitaxy region with n-type dopants.
6. The method of claim 5 , wherein forming the second doped region over portions of the second semiconductor fin further comprises:
forming a second epitaxy region over the second semiconductor fin; and
doping the second epitaxy region with p-type dopants.
7. The method of claim 1 , wherein amorphizing the exposed doped regions further comprises exposing the doped regions to a neutral element pre-amorphization ion implantation (PAI).
8. The method of claim 7 , wherein the neutral element PAI comprises Ge or Si dopants.
9. The method of claim 1 , wherein recrystallizing the amorphized doped regions further comprises exposing the doped regions to a laser spike anneal for solid phase epitaxy (LSA SPE) process.
10. The method of claim 9 , wherein the recrystallized doped regions each comprise a dopant concentration of about 7×10 20 cm −3 to about 2×10 21 cm −3 .
11. A method for fabricating a semiconductor device, the method comprising:
forming a plurality of semiconductor fins opposite a surface of a substrate;
forming an epitaxy region over each of the plurality of semiconductor fins, a first portion of the epitaxy regions comprising n-type dopants and a second portion of the epitaxy regions comprising p-type dopants, the first and second portions arranged into adjacent pairs of epitaxy regions comprising a first epitaxy region doped with n-type dopants and a second epitaxy region doped with p-type dopants;
prior to forming a replacement metal gate (RMG), forming a shared trench exposing a portion of the first and second epitaxy regions over each pair;
concurrently amorphizing the epitaxy regions; and
concurrently recrystallizing the epitaxy regions.
12. The method of claim 11 , wherein the n-type dopants are selected from the group consisting of As, P, and Sb.
13. The method of claim 11 , wherein the p-type dopants are selected from the group consisting of B, BF 2 , Al, and Ga.
14. The method of claim 11 , wherein amorphizing the epitaxy regions further comprises exposing the epitaxy regions to a neutral element pre-amorphization ion implantation (PAI).
15. The method of claim 14 , wherein the neutral element PAI comprises Ge or Si dopants.
16. The method of claim 11 , wherein recrystallizing the epitaxy regions further comprises exposing the epitaxy regions to a laser spike anneal for solid phase epitaxy (LSA SPE) process.
17. The method of claim 16 , wherein the recrystallized epitaxy regions each comprise a dopant concentration of about 7×10 20 cm −3 to about 2×10 21 cm −3 .