Plasma treated metal silicide layer formation
View Patent ↗Devices and methods for plasma treated metal silicide layer formation are disclosed. In one embodiment, a method for manufacturing a semiconductor device comprises forming a metal layer on a silicon substrate, exposing the metal layer to a plasma, and thermally treating the silicon substrate and the metal layer to form a metal silicide layer.
1. A method for manufacturing a flash memory device, comprising:
forming a laminated gate on a silicon substrate;
forming a source region and a drain region in the silicon substrate;
forming a sidewall on each side of the laminated gate;
forming a metal layer on exposed areas of the silicon substrate and on the laminated gate, wherein the metal layer comprises titanium, cobalt and nickel;
forming a metal nitride layer on the metal layer;
exposing the metal nitride layer to a plasma; and
thermally treating the silicon substrate, the metal layer, and the metal nitride layer to form a metal silicide layer.
2. The method for manufacturing the flash memory device according to claim 1 , wherein the forming the laminated gate comprises:
forming a tunnel oxide film on the silicon substrate;
forming a floating gate on the tunnel oxide film;
forming an integrated insulating film on the floating gate; and
forming a control gate on the integrated insulating film.
3. The method for manufacturing the flash memory device according to claim 1 , wherein the forming the source region and the drain region comprises implanting arsenic to the silicon substrate using the laminated gate as a mask.
4. The method for manufacturing the flash memory device according to claim 1 , wherein the plasma comprises a reducing gas and an inactive gas.
5. The method for manufacturing the flash memory device according to claim 1 , wherein the plasma comprises nitrogen and hydrogen.
6. The method for manufacturing the flash memory device according to claim 1 , wherein the metal layer is approximately 10 nm thick and the metal nitride layer is approximately 30 nm thick.
7. The method for manufacturing the flash memory device according to claim 1 , wherein the plasma is applied to the metal nitride layer for at least 35 seconds with a radio frequency (RF) power ranging between 650 watts to 850 watts.
8. The method for manufacturing the flash memory device according to claim 1 , wherein the plasma comprises a reducing gas.
9. The method for manufacturing the flash memory device according to claim 1 , wherein the plasma is applied to the metal layer for at least 35 seconds.
10. The method for manufacturing the flash memory device according to claim 1 , wherein the plasma is applied to the metal layer with a radio frequency (RF) power ranging between 650 watts to 850 watts.
11. The method for manufacturing the flash memory device according to claim 1 , wherein forming the metal layer on the silicon substrate is performed by a sputtering method.
12. A method for manufacturing a flash memory device, comprising:
forming a laminated gate on a silicon substrate;
forming a sidewall on each side of the laminated gate;
forming an interlayer insulating film on the laminated gate and on the sidewalls;
forming a contact hole in the interlayer insulating film;
forming a metal layer on the inner surfaces of the contact hole and on the interlayer insulating film;
forming a metal nitride layer on the metal layer;
exposing the metal nitride layer to a plasma; and
thermally treating the silicon substrate, the metal layer, and the metal nitride layer to form a metal silicide layer.
13. The method for manufacturing the flash memory device according to claim 12 , wherein the metal layer comprises at least one of titanium, cobalt and nickel.
14. The method for manufacturing the flash memory device according to claim 12 further comprising forming a bit line into the silicon substrate before forming the laminated gate on the silicon substrate.
15. The method for manufacturing the flash memory device according to claim 14 , wherein the contact hole is in contact with the bit line.
16. The method for manufacturing the flash memory device according to claim 12 further comprising forming a plug metal inside the contact hole.
17. The method for manufacturing the flash memory device according to claim 16 , wherein the plug metal comprises tungsten.
18. The method for manufacturing the flash memory device according to claim 12 , wherein forming the metal silicide layer removes remaining portions of the metal layer and metal nitride layer.
19. The method for manufacturing the flash memory device according to claim 16 , wherein forming the metal silicide layer retains remaining portions of the metal nitride layer in the contact hole as a barrier layer between the plug metal and the metal silicide layer.