Transistor having airgap spacer around gate structure
An integrated semiconductor device having a gate structure adjacent to a semiconductor body at a channel region, the channel region being positioned laterally between source/drain regions. Metal plugs are on the source/drain regions, and rectangular-shaped or trapezoidal-shaped plug caps are above and immediately adjacent to the metal plugs. A self-aligned metal filled contact (CA) is conductively coupled to one of the metal plugs on the source and drain regions, and a self-aligned metal filled contact (CBoA) is conductively coupled to the gate structure. The device further includes a low k dielectric layer that includes a continuous airgap having an inverted u-shape formed about the gate structure and breaks at about a portion of the gate structure including the self-aligned metal filled contact (CBoA). Also, methods for forming the device including the uniquely shaped continuous airgap are disclosed.
1. A method for forming a device structure, the method comprising:
forming an opening including a lower portion and a trapezoidal-shaped upper portion in a first sacrificial cap material to source and drain regions;
metallizing the lower portion to form metal plugs conductively coupled to the source and drain regions;
filling the trapezoidal-shaped upper portions with a second sacrificial cap material;
forming a self-aligned contact opening (CA) to at least one of the metal plugs over the source and drain regions and a self-aligned contact opening over an active area of a gate structure (CBoA);
metallizing the self-aligned contact opening to form a contact area and a gate structure contact area over the active area conductively coupled to the source and drain regions, and the gate structure, respectively;
selectively removing the first sacrificial cap material from top surfaces of the source and drain regions; and
depositing a low k dielectric material to form a continuous airgap extending from between sidewalls and above the gate structure.
2. The method of claim 1 , wherein the continuous airgap has an inverted U-shape.
3. The method of claim 1 , wherein forming the self-aligned contact opening (CA) to the at least one of the metal plugs includes directionally etching through the second sacrificial cap material in the trapezoidal-shaped upper portions.
4. The method of claim 1 , wherein forming the self-aligned contact opening to the gate structure (CBoA) includes directionally etching through the first sacrificial cap material between adjacent to the filled trapezoidal-shaped upper portions.
5. The method of claim 1 , further comprising: removing the first sacrificial cap material in an amount effective to form a bottom spacer layer.
6. The method of claim 1 , wherein the gate structure comprises a replacement metal gate structure.
7. An integrated circuit structure comprising:
a gate structure formed adjacent to a semiconductor body at a channel region, wherein the channel region is positioned laterally between source/drain regions;
metal plugs formed on the source/drain regions;
trapezoidal-shaped plug caps formed above and immediately adjacent to the metal plugs;
a self-aligned metal filled contact conductively coupled to one of the metal plugs on the source/drain regions;
a self-aligned metal filled contact formed over an active area conductively coupled to the gate structure; and
a low k dielectric layer comprising a continuous airgap having an inverted U-shape formed around the gate structure and breaks at about a portion of the gate structure including the self-aligned metal filled contact.
8. The integrated circuit structure of claim 7 , wherein the self-aligned metal filled contact conductively coupled to the gate structure is self-aligned to and has a width about equal to a distance between adjacent trapezoidal-shaped plug caps.
9. The integrated circuit structure of claim 7 , further comprising a protective layer on surfaces intermediate the low k dielectric layer and the gate structure, the metal plugs, a metal plug cap, and a bottom isolation layer.
10. The integrated circuit structure of claim 9 , wherein the metal plug cap comprises SiC.
11. The integrated circuit structure of claim 7 , wherein the continuous airgap in a region including the self-aligned metal filled contact is enclosed by a metal plug cap, the metal plugs, the gate structure, and a gate contact.
12. The integrated circuit structure of claim 7 , further comprising one or more replacement metal gate structures, wherein the continuous airgap has the inverted U-shape formed about the replacement metal gate structure.
13. The integrated circuit structure of claim 7 , wherein the trapezoidal-shaped plug caps above and immediately adjacent to the metal plugs define a space therebetween, wherein the self-aligned metal filled contact is self-aligned to the space.
14. The integrated circuit structure of claim 7 , wherein the source/drain regions are raised relative to the fin and formed of an epitaxial semiconductor material.
15. An integrated circuit structure comprising:
a gate structure formed adjacent to a semiconductor body at a channel region, wherein the channel region is positioned laterally between source/drain regions;
metal plugs formed on the source/drain regions;
rectangular-shaped plug caps formed above and immediately adjacent to the metal plugs;
a self-aligned metal filled contact (CA) conductively coupled to one of the metal plugs on the source/drain regions;
a self-aligned metal filled contact formed over an active area (CBoA) between adjacent rectangular shaped plug caps conductively coupled to the gate structure in the active area; and
a dielectric spacer comprising a continuous airgap having an inverted U-shape formed around the gate structure when the rectangular-shaped plug caps are adjacent to one another and breaks at an edge of the active area and about a portion of the gate structure including the self-aligned metal filled contact.
16. The integrated circuit structure of claim 15 , wherein the self-aligned metal filled contact conductively coupled to the gate structure is self-aligned to and has a width equal to a distance between adjacent rectangular-shaped plug caps.
17. The integrated circuit structure of claim 15 , further comprising a discontinuous airgap in the active area enclosed by the rectangular shaped plug caps, the metal plugs, the gate structure, and a gate contact.
18. The integrated circuit structure of claim 15 , wherein the source/drain regions are raised relative to the fin and formed of an epitaxial semiconductor material.
19. The integrated circuit structure of claim 15 , wherein the continuous airgap formed in a region including the CBoA is enclosed by a metal plug cap, the metal plugs, the gate structure, and a gate contact.
20. The integrated circuit structure of claim 15 , further comprising one or more replacement metal gate structures, wherein the continuous airgap has the inverted U-shape formed around the replacement metal gate structure.