High voltage FINFET structure
View Patent ↗Methods for forming FIN-shaped field effect transistors (FINFETs) capable of withstanding high voltage applications and the resulting devices are disclosed. Embodiments include forming a source and a drain on a substrate, forming a thin body (FIN) on the substrate and connecting the source and the drain, forming a gate over top and side surfaces of a first part of the FIN, thereby defining a drain-side FIN region of the FIN between the gate and the drain, and forming a shielding region over top and side surfaces of a second part of the FIN in the drain-side FIN region.
1. A method comprising:
forming a source and a drain on a substrate;
forming a thin body (FIN) on the substrate and connecting the source and the drain;
forming a gate over top and side surfaces of a first part of the FIN, thereby defining a drain-side FIN region of the FIN between the gate and the drain;
forming a shielding region over top and side surfaces of a second part of the FIN in the drain-side FIN region;
forming a first dielectric layer over the top and the side surfaces of the first part of the FIN prior to forming the gate; and
forming a second dielectric layer over the top and the side surfaces of the second part of the FIN in the drain-side FIN region prior to forming the shielding region,
wherein the second dielectric layer is thicker than the first dielectric layer.
2. The method according to claim 1 , further comprising forming one or more additional shielding regions over top and side surfaces of the FIN in the drain-side FIN region between the first shielding region and the drain.
3. The method according to claim 2 , further comprising independently biasing the first shielding region and the one or more additional shielding regions.
4. The method according to claim 2 , further comprising shorting together the shielding region and the one or more additional shielding regions.
5. The method according to claim 2 , further comprising:
forming one or more dielectric layers over top and side surfaces of respective portions of the FIN prior to forming the one or more additional shielding regions,
wherein the one or more dielectric layers have thicknesses different from the first dielectric layer.
6. The method according to claim 1 , further comprising implanting a dopant in the substrate within the drain-side FIN region below the shielding region, the dopant being of a type that is opposite a type of dopant used in doping the drain-side FIN region, forming a reverse implant region.
7. The method according to claim 1 , wherein the shielding region forms a second gate, and the second gate is floating, separately biased, grounded or shorted with the gate.
8. The device according to claim 7 , wherein the gate and the second gate are made of different gate materials.
9. A device comprising:
a substrate;
a source and a drain on the substrate;
a thin body (FIN) on the substrate and connecting the source and the drain;
a gate over top and side surfaces of a first part of the FIN and defining a drain-side FIN region of the FIN between the gate and the drain;
a shielding region over top and side surfaces of a second part of the FIN in the drain-side FIN region;
a first dielectric layer between the gate and the first part of the FIN; and
a second dielectric layer between the shielding region and the second part of the FIN in the drain-side FIN region,
wherein the second dielectric layer is thicker than the first dielectric layer.
10. The device according to claim 9 , further comprising one or more additional shielding regions over top and side surfaces of the FIN in the drain-side FIN region between the shielding region and the drain.
11. The device according to claim 10 , comprising the shielding region and the one or more additional shielding regions being independent-biased.
12. The device according to claim 10 , comprising the shielding region and the one or more additional shielding regions being shorted together.
13. The device according to claim 10 , further comprising one or more dielectric layers respectively between the one or more additional shielding regions and the FIN, the one or more dielectric layers having thicknesses different from the first dielectric layer.
14. The device according to claim 9 , further comprising a reverse implant region in the substrate within the drain-side FIN region below the shielding region.
15. The device according to claim 9 , wherein the shielding region forms a second gate, and the second gate is floating, separately biased, grounded or shorted with the gate.
16. The device according to claim 15 , wherein the gate and the second gates are formed of different gate materials.
17. A method comprising:
forming a source and a drain on a substrate;
forming a thin body (FIN) on the substrate and connecting the source and the drain;
forming a first dielectric layer of a first thickness over top and side surfaces of a first part of the FIN;
forming a second dielectric layer of a second thickness over top and side surfaces of a second part of the FIN, the second part of the FIN located between the first dielectric layer and the drain, the second part of the FIN constituting a drain side-FIN region, wherein the second thickness is greater than the first thickness and adjacent side surfaces of the first dielectric layer and the second dielectric layer are contiguous thereby forming a stepped dielectric layer; and
forming a gate over the stepped dielectric layer.