Hybrid source and drain contact formation using metal liner and metal insulator semiconductor contacts
An electrical device including a first semiconductor device having a silicon and germanium containing source and drain region, and a second semiconductor device having a silicon containing source and drain region. A first device contact to at least one of said silicon and germanium containing source and drain region of the first semiconductor device including a metal liner of an aluminum titanium and silicon alloy and a first tungsten fill. A second device contact is in contact with at least one of the silicon containing source and drain region of the second semiconductor device including a material stack of a titanium oxide layer and a titanium layer. The second device contact may further include a second tungsten fill.
1. A method of forming contacts to an electrical device comprising:
providing a first via to a first semiconductor device comprising at least one of a silicon and germanium containing source and drain region and providing a second via to a second semiconductor device comprising at least one of a silicon containing source and drain region;
forming a material stack in the first and second via, the first material stack comprising a first metal layer and a second metal layer;
converting the second metal layer of the first material stack within the second via to a second metal oxide;
removing the second metal oxide with an etch that is selective to the first metal layer;
converting the first metal layer present in the second via to first metal oxide with an oxidation anneal, wherein during said oxidation anneal the second metal layer in the first via alloys with the first metal layer and silicon from the silicon and germanium containing source and drain region to provide a binary metal semiconductor alloy;
depositing a cap metal layer in the second via; and
depositing a metal fill in one at least one of the first and second via.
2. The method of claim 1 further comprising forming a first tungsten layer filling the first and second via after forming the material stack.
3. The method of claim 2 further comprising forming a block mask over the first via, and removing the first tungsten layer from the second via.
4. The method of claim 3 , wherein removing the first tungsten layer from the second via comprises an etch that is selective to the second metal layer that is present in the second via, wherein the etch comprises reactive ion etch with a SF 6 based chemistry or a wet etch comprising NH 4 OH:H 2 O 2 :H 2 O in a ratio of 1:1.5:50 at 20° C. to 25° C.
5. The method of claim 1 , wherein the converting of the second metal layer of the first material stack within the second via to the second metal oxide comprises an oxygen plasma treatment.
6. The method of claim 1 , wherein said removing the second metal oxide with said etch that is selective to the titanium layer comprises a wet etch comprising NH 4 OH: H 2 O at a ratio ranging from 1:10 to 1:300 at a temperature ranging from 25° C. to 65° C., or a wet etch of diluted TMAH.
7. The method of claim 1 , wherein depositing the cap metal layer in the second via comprises deposition of titanium using chemical vapor deposition, physical vapor deposition, atomic layer deposition or a combination thereof.
8. The method of claim 3 , said depositing the metal fill comprises depositing tungsten directly atop the metal layer in the second via and tungsten atop the first tungsten layer in the first via, and planarizing the tungsten fill.
9. A method of forming contacts to an electrical device comprising:
providing a first via to a first semiconductor device comprising at least one of a silicon and germanium containing source and drain region, and a second via to a second semiconductor device comprising at least one of a silicon containing source and drain region;
forming a material stack in the first and second via, the first material stack comprising a first metal layer at a base of said first and second via, a second metal layer on the first metal layer, and a tungsten fill;
removing the tungsten fill and the second metal layer from the second via;
converting the first metal layer present in the second via to a first metal oxide with an oxidation anneal, wherein during said oxidation anneal the second metal layer in the first via alloys with the first metal layer and silicon from the silicon and germanium containing source and drain region to provide a binary metal semiconductor alloy;
depositing a titanium layer in the second via; and
depositing tungsten in the second via.
10. The method of claim 9 , wherein said removing the tungsten fill and the second metal layer from the second via comprises:
forming a block mask over the first via;
removing the tungsten fill from the second via;
converting the second metal layer within the second via to a second metal oxide; and
removing the second metal oxide with an etch that is selective to the titanium layer.
11. The method of claim 10 , wherein removing the tungsten fill from the second via comprises an etch that is selective to the second metal layer that is present in the second via, wherein the etch comprises reactive ion etch with a SF 6 based chemistry or a wet etch comprising NH 4 OH:H 2 O 2 :H 2 O in a ratio of 1:1.5:50 at 20° C. to 25° C.
12. The method of claim 10 , wherein the converting of the second metal layer within the second via to the second metal oxide comprises an oxygen plasma treatment.
13. The method of claim 10 , wherein said removing the second metal oxide with said etch that is selective to the first metal layer comprises a wet etch comprising NH 4 OH:H 2 O at a ratio ranging from 1:10 to 1:300 at a temperature ranging from 25° C. to 65° C., or a wet etch of diluted TMAH.
14. The method of claim 9 , wherein depositing a first metal layer in the second via comprises chemical vapor deposition, physical vapor deposition, atomic layer deposition or a combination thereof.
15. The method of claim 9 , said depositing the tungsten in the second via comprises depositing tungsten directly atop the first metal layer in the second via and tungsten atop the first tungsten layer in the first via, and planarizing the tungsten fill.