Semiconductor devices and methods of fabrication with reduced gate and contact resistances
Semiconductor structures with reduced gate and/or contact resistances and fabrication methods are provided. The method includes: providing a semiconductor device, which includes forming a transistor of the semiconductor device, where the transistor forming includes: forming a T-shaped gate for the transistor, the T-shaped gate being T-shaped in elevational cross-section; and forming an inverted-T-shaped contact to an active region of the transistor, the inverted-T-shaped contact including a conductive structure with an inverted T-shape in elevational cross-section.
1. A method comprising:
providing a semiconductor device, the providing comprising:
forming a transistor of the semiconductor device, the forming comprising;
forming a T-shaped gate for the transistor, the T-shaped gate being T-shaped in elevational cross-section; and
forming an inverted-T-shaped contact to an active region of the transistor, the inverted-T-shaped contact comprising a conductive structure with an inverted-T-shape in elevational cross-section, wherein the inverted-T-shaped contact is self-aligned, at least in part, to the T-shaped gate.
2. The method of claim 1 , wherein forming the transistor further comprises providing a sidewall spacer adjacent to the T-shaped gate of the transistor and at least partially separating the T-shaped gate and the inverted-T-shaped contact, and wherein a portion of the T-shaped gate extends over the sidewall spacer.
3. The method of claim 2 , wherein the sidewall spacer is a first sidewall spacer and wherein forming the transistor further comprises providing a second sidewall spacer adjacent to the T-shaped gate and at least partially separating the T-shaped gate and the inverted-T-shaped contact of the transistor, the second sidewall spacer residing, at least partially, above the first sidewall spacer.
4. The method of claim 3 , wherein forming the transistor further comprises providing the second sidewall spacer with an outer wall away from the T-shaped gate extending beyond an outer wall of the first sidewall spacer away from the T-shaped gate.
5. The method of claim 3 , wherein the second sidewall spacer comprises a reverse sidewall spacer disposed adjacent to a sidewall of the T-shaped gate of the transistor.
6. The method of claim 3 , wherein the first sidewall spacer comprises a first material and the second sidewall spacer comprises a second material, the first material and the second material being different materials, and wherein the second material has a dielectric constant less than that of the first material.
7. The method of claim 6 , wherein the first material comprises a nitride and the second material comprises at least one of an oxide or a nitride.
8. The method of claim 6 , wherein the dielectric constant of the second material is less than that of silicon nitride.
9. The method of claim 1 , wherein forming the inverted-T-shaped contact comprises forming the conductive structure over and in electrical contact with a silicide, and the silicide residing over or comprising part of the active region, and the active region being one of a drain region or a source region of the transistor.
10. The method of claim 1 , wherein forming the T-shaped gate comprises forming a horizontal portion of the T-shaped gate over a vertical portion of the T-shaped gate, the horizontal portion extending substantially symmetrically laterally out from the vertical portion of the T-shaped gate, and wherein forming the transistor further comprises providing another inverted-T-shaped contact, the another inverted-T-shaped contact also being self-aligned, at least in part, to the T-shaped gate of the transistor and being on an opposite side of the T-shaped gate from the inverted-T-shaped contact.
11. The method of claim 1 , wherein forming the T-shaped gate comprises forming a horizontal portion of the T-shaped gate over a vertical portion of the T-shaped gate, the horizontal portion extending asymmetrical laterally out from the vertical portion of T-shaped gate, and wherein forming the transistor further comprises providing another contact, the another contact being non-self-aligned to the T-shaped gate of the transistor, and being on an opposite side of the T-shaped gate from the inverted-T-shaped contact.
12. A semiconductor device comprising:
a transistor, the transistor comprising;
a substrate;
a T-shaped gate disposed over the substrate, the T-shaped gate being T-shaped in elevational cross-section; and
an inverted-T-shaped contact to an active region of the transistor, the inverted-T-shaped contact comprising a conductive structure with an inverted-T-shape in elevational cross-section, wherein the inverted-T-shaped contact is self-aligned at least in part, to the T-shaped gate.
13. The semiconductor device of claim 12 , further comprising a sidewall spacer disposed adjacent to the T-shaped gate and at least partially separating the T-shaped gate and the inverted-T-shaped contact, and wherein a portion of the T-shaped gate extends over the sidewall spacer.
14. The semiconductor device of claim 13 , wherein the sidewall spacer is a first sidewall spacer and the semiconductor device further comprises a second sidewall spacer disposed adjacent to the T-shaped gate and at least partially separating the T-shaped gate and the inverted-T-shaped contact of the transistor, the second sidewall spacer residing, at least partially, above the first sidewall spacer.
15. The semiconductor device of claim 14 , wherein the second sidewall spacer comprises an outer wall away from the T-shaped gate extending beyond an outer wall of the first sidewall spacer away from the T-shaped gate.
16. The semiconductor device of claim 15 , wherein the first sidewall spacer comprises a first material and the second sidewall comprises a second material, the first material and the second material being different materials, and wherein the second material has a dielectric constant less than that of the first material.
17. The semiconductor device of claim 16 , wherein the first material comprises a nitride and the second material comprises at least one of an oxide or a nitride.
18. The semiconductor device of claim 12 , wherein the inverted-T-shaped contact comprises the conductive structure residing over and in electrical contact with a silicide, the silicide residing over or comprising part of the active region, and the active region being one of a drain region or a source region of the transistor.
19. The semiconductor device of claim 12 , wherein the T-shaped gate comprises a horizontal portion of the T-shaped gate over a vertical portion of the T-shaped gate, the horizontal portion extending substantially symmetrically laterally out from the vertical portion of the T-shaped gate, and wherein the semiconductor device further comprises another inverted-T-shaped contact, the another inverted-T-shaped contact also being self-aligned, at least in part, to the T-shaped gate of the transistor and being on an opposite side of the T-shaped gate from the inverted-T-shaped contact.
20. The semiconductor device of claim 12 , wherein the T-shaped gate comprises a horizontal portion of the T-shaped gate over a vertical portion of the T-shaped gate, the horizontal portion extending asymmetrical laterally out from the vertical portion of the T-shaped gate, and wherein the semiconductor device further comprises another contact, the another contact being non-self-aligned to the T-shaped gate of the transistor, and being on an opposite side of the T-shaped gate from the inverted-T-shaped contact.