Fully silicided linerless middle-of-line (MOL) contact
A method of making a semiconductor device includes forming a source/drain region on a substrate; disposing a gate stack on the substrate and adjacent to the source/drain region, the gate stack including a gate spacer along a sidewall of the gate stack; disposing an inter-level dielectric (ILD) layer on the source/drain region and the gate stack; removing a portion of the ILD layer on the source/drain region to form a source/drain contact pattern; filling the source/drain contact pattern with a layer of silicon material, the layer of silicon material being in contact with the source/drain region and in contact with the gate spacer; depositing a metallic layer over the first layer of silicon material; and performing a silicidation process to form a source/drain contact including a silicide.
1. A method of making a semiconductor device, the method comprising:
forming a source/drain region on a substrate;
disposing a gate stack on the substrate and adjacent to the source/drain region, the gate stack comprising a gate spacer along a sidewall of the gate stack;
disposing an inter-level dielectric (ILD) layer on the source/drain region and the gate stack;
removing a portion of the ILD layer on the source/drain region to form a source/drain contact pattern;
filling the source/drain contact pattern with a layer of silicon material, the layer of silicon material being in contact with the source/drain region and in contact with the gate spacer;
depositing a metallic layer over the layer of silicon material; and
performing a silicidation process to form a source/drain contact comprising a silicide, the silicide of the source/drain contact extending continuously from the gate spacer to a second gate spacer of an adjacent second gate stack.
2. The method of claim 1 , wherein the silicidation process includes a low temperature annealing process.
3. The method of claim 2 , wherein the low temperature annealing process substantially fully consumes the silicon material to form the metal silicide.
4. The method of claim 3 , wherein the metal silicide is nickel silicide.
5. The method of claim 2 , wherein the low temperature annealing process is performed at a temperature in a range from about 300 to about 600° C.
6. The method of claim 1 , wherein the metallic layer comprises a refractory metal.
7. The method of claim 1 , wherein the source/drain contact consists essentially of the silicide.
8. The method of claim 1 , wherein filling the source/drain contact pattern with the silicide further comprises depositing another silicon layer onto the metallic layer and depositing another a metallic layer onto the another silicon layer.
9. The method of claim 1 , wherein performing the silicidation process comprises performing a thermal annealing process at a temperature in a range from about 300 to about 600° C.
10. The method of claim 1 , further comprising pre-cleaning the source/drain contact pattern after removing a portion of the ILD layer.