Contacts-first self-aligned carbon nanotube transistor with gate-all-around
A method of fabricating a semiconducting device is disclosed. A carbon nanotube is deposited on a substrate of the semiconducting device. A first contact on the substrate over the carbon nanotube. A second contact on the substrate over the carbon nanotube, wherein the second contact is separated from the first contact by a gap. A portion of the substrate in the gap between the first contact and the second contact is removed.
1. A method of fabricating a semiconducting device, comprising:
forming a carbon nanotube on a substrate;
forming a first contact on the substrate over the carbon nanotube;
forming a second contact on the substrate over the carbon nanotube, wherein the second contact is separated from the first contact by a gap;
removing a portion of the substrate to form a recess in the substrate in the gap between the first contact and the second contact; and
depositing a gate material of the semiconducting device to fill the recess.
2. The method of claim 1 , wherein removing the substrate in the gap between the first contact and the second contact forms a carbon nanotube bridge over the recess.
3. The method of claim 2 , further comprising depositing the gate material of the semiconducting device in the gap to define a gate that surrounds the carbon nanotube bridge.
4. The method of claim 3 , further comprising depositing high-k dielectric material annularly on the carbon nanotube bridge prior to depositing gate material in the recess.
5. The method of claim 3 , further comprising polishing the deposited gate material to so as to provide a surface of the gate material coplanar with surfaces of the first contact and the second contact.
6. The method of claim 3 , further comprising recessing a portion of the gate material above the carbon nanotube bridge to a level below a top surface of the first and second contacts.
7. The method of claim 1 , further comprising forming the first contact and the second contact aligned to provide a self-aligned gate structure of the semiconducting device.
8. The method of claim 1 , wherein removing the substrate further comprises anisotropic etching of the substrate.
9. A method of fabricating a transistor, comprising:
forming a carbon nanotube material on a substrate;
forming a first contact and a second contact on the substrate and over the carbon nanotube material to define a gap between the first contact and the second contact;
removing a portion of the substrate in the gap to form a recess in the substrate between the first contact and the second contact; and
depositing a gate material of the transistor to fill the recess.
10. The method of claim 9 , further comprising removing the substrate in the gap to form a carbon nanotube bridge over the recess.
11. The method of claim 10 , further comprising depositing gate material of the transistor in the gap to provide a gate material all around the carbon nanotube bridge.
12. The method of claim 11 , further comprising depositing a dielectric material annularly conforming to the carbon nanotube bridge prior to depositing gate material in the recess.
13. The method of claim 11 , further comprising polishing the deposited gate material to perform one of: providing a surface of the gate material coplanar with surfaces of the one or more contacts.
14. The method of claim 11 , further comprising recessing a portion of the gate material above the carbon nanotube bridge to a level below a top surface of the first and second contacts.
15. The method of claim 9 , further comprising forming the first contact and the second contact to provide a self-aligned gate structure of the transistor.
16. A method of making a self-aligned carbon nanotube transistor, comprising:
forming a carbon nanotube on a substrate;
forming a source contact on the substrate over the carbon nanotube;
forming a drain contact on the substrate over the carbon nanotube, wherein the drain contact is separated from the source contact by a gap;
removing a portion of the substrate in the gap to form a recess in the substrate between the source contact and the drain contact; and
depositing a gate material to fill the recess.
17. The method of claim 16 , wherein removing the substrate in the gap between the source contact and the drain contact forms a carbon nanotube bridge over the recess.
18. The method of claim 17 , further comprising depositing gate material in the gap to surround the carbon nanotube bridge.
19. The method of claim 18 , further comprising depositing conformal high-k dielectric material annularly on the carbon nanotube bridge prior to depositing the gate material in the recess.
20. The method of claim 16 , wherein removing the substrate further comprises anisotropic etching of the substrate.