Semiconductor structure and method for forming the same
A semiconductor structure and a method for forming the same are provided. A semiconductor structure includes a substrate, a seed layer on the substrate, an epitaxial layer on the seed layer, a first transistor on the epitaxial layer, an interlayer dielectric layer on the epitaxial layer, a dielectric pillar penetrating through the interlayer dielectric layer and the epitaxial layer, and a conductive liner disposed on a sidewall of the dielectric pillar. The conductive liner is electrically connected to the first transistor and the seed layer.
1. A semiconductor structure, comprising:
a substrate;
a seed layer on the substrate;
an epitaxial layer on the seed layer;
a first transistor on the epitaxial layer;
an interlayer dielectric layer on the epitaxial layer;
a dielectric pillar penetrating through the interlayer dielectric layer and the epitaxial layer; and
a conductive liner disposed on a sidewall of the dielectric pillar, wherein the conductive liner is electrically connected to the first transistor and the seed layer.
2. The semiconductor structure as claimed in claim 1 , further comprising a first metal layer electrically connected to the conductive liner and the first transistor.
3. The semiconductor structure as claimed in claim 2 , wherein the first metal layer is electrically connected to the conductive liner and a first source structure of the first transistor.
4. The semiconductor structure as claimed in claim 1 , wherein the conductive liner is further disposed on another sidewall opposite the sidewall of the dielectric pillar.
5. The semiconductor structure as claimed in claim 4 , further comprising:
a second transistor on the epitaxial layer and adjacent to the another sidewall of the dielectric pillar; and
a second metal layer spans over the conductive liner and the second transistor, wherein the second metal layer is connected to one end of the conductive liner on the another sidewall.
6. The semiconductor structure as claimed in claim 5 , wherein the second metal layer is electrically connected to the conductive liner and a second source structure of the second transistor.
7. The semiconductor structure as claimed in claim 1 , wherein a bottom of the dielectric pillar is not lower than a bottom of the conductive liner.
8. The semiconductor structure as claimed in claim 1 , wherein the dielectric pillar further penetrates through the seed layer and contacts the substrate.
9. The semiconductor structure as claimed in claim 1 , further comprising an isolation structure around the dielectric pillar.
10. The semiconductor structure as claimed in claim 1 , wherein the first transistor is a high electron mobility transistor (HEMT).
11. A method for forming a semiconductor structure, comprising:
providing a substrate;
forming a seed layer on the substrate;
forming an epitaxial layer on the seed layer;
forming a first transistor on the epitaxial layer;
forming an interlayer dielectric layer on the epitaxial layer and covering the first transistor;
forming a through hole penetrating through the interlayer dielectric layer and the epitaxial layer to expose a portion of a surface of the seed layer;
forming a conductive liner on a sidewall of the through hole, wherein the conductive liner is electrically connected to the first transistor and the seed layer; and
filling the through hole with a dielectric filler to form a dielectric pillar.
12. The method as claimed in claim 11 , wherein the formation of the conductive liner comprises:
forming the conductive liner on a bottom and sidewalls of the through hole and on the interlayer dielectric layer; and
removing the conductive liner on the bottom of the through hole and on the interlayer dielectric layer.
13. The method as claimed in claim 11 , further comprising forming a first metal layer after forming the dielectric pillar, wherein the first metal layer is electrically connected to the conductive liner and the first transistor.
14. The method as claimed in claim 13 , wherein the first metal layer is electrically connected to the conductive liner and a first source structure of the first transistor.
15. The method as claimed in claim 11 , wherein the formation of the conductive liner further comprises forming the conductive liner on another sidewall opposite the sidewall of the through hole.
16. The method as claimed in claim 15 , further comprising:
forming a second transistor on the epitaxial layer and adjacent to the another sidewall of the dielectric pillar; and
forming a second metal layer after forming the dielectric pillar, wherein the second metal layer spans over the conductive liner and the second transistor, and is connected to one end of the conductive liner on the another sidewall.
17. The method as claimed in claim 16 , wherein the second metal layer is electrically connected to the conductive liner and a second source structure of the second transistor.
18. The method as claimed in claim 11 , wherein the through hole further penetrates through the seed layer to expose the substrate.
19. The method as claimed in claim 11 , further comprising forming an isolation structure around the through hole before forming the interlayer dielectric layer.
20. The method as claimed in claim 19 , wherein the isolation structure is formed by (i) breaking a crystal lattice structure of the epitaxial layer by applying external energy; (ii) implanting a non-conductive element into the epitaxial layer; or (iii) filling a dielectric material into the epitaxial layer.