Methods for electrical isolation of transistors
Methods for isolating two adjacent transistors are disclosed. A substrate has a first semiconducting fin on a first region and a second semiconducting fin on a second region, and the first semiconducting fin and the second semiconducting fin contact each other at a jog region. A dummy gate within or adjacent the jog region is removed to expose a portion of the first semiconducting fin and form an isolation volume. Etching is performed to remove the exposed portion of the first semiconducting fin and create a trench in the substrate. The trench and the isolation volume are filled with at least one dielectric material to form an electrically isolating structure between the first region and the second region. Additional dummy gates in each region can be removed and replaced with an electrically conductive material to form two adjacent transistors electrically isolated from each other.
1 . A method for isolating a first region from a second region on a substrate, comprising:
removing a dummy gate in a jog region between the first region and the second region to expose a portion of a semiconducting fin and form an isolation volume;
etching to remove the exposed portion of the semiconducting fin and create a trench in the substrate; and
filling the trench and the isolation volume with at least one dielectric material to form a CPODE structure that isolates the first region from the second region.
2 . The method of claim 1 , wherein a portion of the semiconducting fin in the first region has a greater width than a portion of the semiconducting fin in the second region.
3 . The method of claim 1 , wherein a portion of the semiconducting fin in the first region is offset from a portion of the semiconducting fin in the second region.
4 . The method of claim 1 , wherein the semiconducting fin splits into multiple portions in the first region, each portion having a smaller width than the semiconducting fin in the second region.
5 . The method of claim 1 , further comprising removing a dummy oxide layer from the exposed portion of the semiconducting fin prior to etching.
6 . The method of claim 1 , wherein walls of the trench and the isolation volume are lined with a first dielectric material and then filled with a second dielectric material.
7 . The method of claim 6 , wherein the first dielectric material is an oxide and the second dielectric material is a nitride.
8 . The method of claim 1 , wherein the semiconducting fin comprises alternating layers of a semiconducting nanosheet and a sacrificial layer.
9 . The method of claim 8 , wherein the sacrificial layers removed after the CPODE structure is formed.
10 . The method of claim 1 , wherein the dummy gate is removed by:
forming a hard mask layer over the substrate;
patterning the hard mask layer to expose the dummy gate; and
etching to remove the dummy gate.
11 . The method of claim 1 , further comprising:
planarizing to expose a second dummy gate in the first region and a third dummy gate in the second region;
etching to remove the second dummy gate and the third dummy gate, forming a gate volume in the first region and a gate volume in the second region; and
depositing an electrically conductive material in the gate volume in the first region and the gate volume in the second region to form a first transistor and a second transistor.
12 . A method for isolating two adjacent transistors, comprising:
receiving a substrate having a first semiconducting fin on a first region and a second semiconducting fin on a second region, wherein the first semiconducting fin and the second semiconducting fin contact each other at a jog region, and wherein each semiconducting fin comprises alternating layers of a semiconducting nanosheet and a sacrificial nanosheet;
removing a dummy gate within or adjacent the jog region to expose a portion of the first semiconducting fin and form an isolation volume;
etching to remove the exposed portion of the first semiconducting fin and create a trench in the substrate;
filling the trench and the isolation volume with at least one dielectric material to form a CPODE structure between the first region and the second region;
planarizing to expose a primary dummy gate in the first region and a secondary dummy gate in the second region;
removing the primary dummy gate, the secondary dummy gate, and the sacrificial nanosheet layers, forming a gate volume in the first region and a gate volume in the second region; and
depositing an electrically conductive material in the gate volume in the first region and the gate volume in the second region to form two adjacent transistors electrically isolated from each other by the CPODE structure.
13 . The method of claim 12 , wherein the first semiconducting fin has a greater width than the second semiconducting fin.
14 . The method of claim 12 , wherein the first region has a plurality of semiconducting fins that contact the second semiconducting fin.
15 . The method of claim 12 , wherein the first semiconducting fin and the second semiconducting fin are offset from each other.
16 . A method for isolating two adjacent transistors, comprising:
removing a dummy gate in a jog region between the two adjacent transistors to expose a portion of a semiconducting fin and form an isolation volume;
etching to remove the exposed portion of the semiconducting fin and create a trench in the substrate;
filling the trench and the isolation volume with at least one dielectric material to form a CPODE structure that isolates the two adjacent transistors from each other.
17 . The method of claim 16 , further comprising removing a dummy oxide layer from the exposed portion of the semiconducting fin prior to etching.
18 . The method of claim 16 , wherein walls of the trench and the isolation volume are lined with a first dielectric material and then filled with a second dielectric material.
19 . The method of claim 18 , wherein the first dielectric material is an oxide and the second dielectric material is a nitride.
20 . The method of claim 16 , further comprising forming a gate electrode in each of the two adjacent transistors after forming the CPODE structure.