High reliability polysilicon components
The present disclosure introduces, among other things, an electronic device, e.g. an integrated circuit (IC). The IC includes a semiconductor substrate comprising a first doped layer of a first conductivity type. A second doped layer of the first conductivity type is located within the first doped layer. The second doped layer has first and second layer portions with a greater dopant concentration than the first doped layer, with the first layer portion being spaced apart from the second layer portion laterally with respect to a surface of the substrate. The IC further includes a lightly doped portion of the first doped layer, the lightly doped portion being located between the first and second layer portions. A dielectric isolation structure is located between the first and second layer portions, and directly contacts the lightly doped portion.
1. An integrated circuit, comprising:
an epitaxial layer over a semiconductor substrate, the epitaxial layer having a first conductivity type and a top surface;
a transistor formed in or over the epitaxial layer, the transistor including a polysilicon gate formed in a gate-layer;
a well region having the first conductivity type located within the epitaxial layer, the well region having first and second well portions with a greater dopant concentration than a dopant concentration of the epitaxial layer, the first well portion spaced apart from the second well portion laterally with respect to the top surface;
a lightly doped portion of the epitaxial layer located between the first and second well portions; and
a dielectric isolation structure located between the first and second well portions and directly contacting the lightly doped portion.
2. The integrated circuit of claim 1 , further comprising a passive component formed in the gate-layer and located directly on the dielectric isolation structure.
3. The integrated circuit of claim 2 , wherein the passive component comprises a resistor.
4. The integrated circuit of claim 2 , wherein the passive component comprises polysilicon.
5. The integrated circuit of claim 1 , further comprising a doped buried layer having a second conductivity type within the epitaxial layer, wherein the lightly doped portion is located between the dielectric isolation structure and the doped buried layer.
6. The integrated circuit of claim 1 , further comprising a transistor located within the well region.
7. The integrated circuit of claim 1 , wherein the first conductivity type is p-type.
8. The integrated circuit of claim 1 , further comprising a second dielectric isolation structure within the well region, and electrically isolated conductive structures located on the well region.
9. An integrated circuit, comprising:
a buried layer formed within an epitaxial layer having a top surface and a first conductivity type and located over a semiconductor substrate, the buried layer having a second opposite conductivity type; and
one or more deep wells having the second conductivity type and extending from the top surface to the buried layer; and
a lightly doped region having the first conductivity type, the lightly doped region surrounded by the buried layer and the one or more deep wells;
a shallow well having the first conductivity type within the lightly doped region; and
a dielectric isolation structure abutting the shallow well having the first conductivity type,
wherein the lightly doped region touches the dielectric isolation structure.
10. The integrated circuit of claim 9 , further comprising a passive component formed in a gate-layer and located over the dielectric isolation structure.
11. The integrated circuit of claim 9 , wherein the dielectric isolation structure is a first dielectric isolation structure, and further comprising a second dielectric isolation structure within the well having the first conductivity type.
12. The integrated circuit of claim 9 , wherein the dielectric isolation structure is a first dielectric isolation structure, and further comprising a second dielectric isolation structure outside the well having the first conductivity type.
13. The integrated circuit of claim 12 , wherein the epitaxial layer touches the second dielectric isolation structure.
14. The integrated circuit of claim 9 , wherein the first conductivity type is p-type.
15. The integrated circuit of claim 9 , further comprising a portion of the epitaxial layer located vertically between the buried layer and the semiconductor substrate.
16. The integrated circuit of claim 9 , wherein the lightly doped region is junction-isolated from the epitaxial layer by the buried layer and the one or more deep wells.
17. An integrated circuit, comprising:
a first well having a first conductivity type within an enclosed portion of a lightly doped epitaxial layer having the first conductivity type, the enclosed portion touching and being bounded laterally by deep wells having a second opposite conductivity type and further touching and being bounded vertically by a buried layer having the second conductivity type connecting the deep wells;
a transistor formed in or over the first well and having a polysilicon gate electrode formed in a gate-layer;
a dielectric isolation structure touching the enclosed portion of the lightly doped epitaxial layer; and
a passive component formed in the gate-layer and located over the dielectric isolation structure.
18. The integrated circuit of claim 17 , wherein the dielectric isolation structure touches the first well.
19. The integrated circuit of claim 17 , wherein the passive component includes a polysilicon resistor.
20. The integrated circuit of claim 17 , further comprising a second well having the first conductivity type located between the dielectric isolation structure and one of the deep wells.
21. The integrated circuit of claim 17 , wherein the first conductivity type is p-type.