Strain engineering in back end of the line
A semiconductor device including at least one semiconductor device on a first surface of a dielectric layer, and at least one stressor structure having an intrinsic stress on a second surface of the dielectric layer. The at least one semiconductor device and the at least one stressor structure are present on opposing sides of the dielectric layer. The at least one stressor structure induces a stress on the at least one semiconductor device opposite the intrinsic stress.
1. A method of forming a semiconductor device comprising:
forming at least one p-type conductivity type semiconductor device in a first region of a dielectric layer and at least one n-type conductivity type device on a second region of the dielectric layer;
forming a first stressor structure corresponding to the first region of the dielectric layer;
forming a second stressor structure corresponding to the second region of the dielectric layer,
forming first and second doped well-regions within the first and second stressor structures, respectively,
forming a first via extending to and contacting the first stressor structure, without contacting the first doped well-region, to enable electrical communication between the at least one p-type conductivity type semiconductor device and the first stressor structure; and
forming a second via extending to and contacting the second stressor structure, without contacting the second doped well-region, to enable electrical communication between the at least one n-type conductivity type semiconductor device and the second stressor structure;
wherein the first doped well-region and the first stressor structure collectively act as a first backgate to the at least one p-type conductivity type semiconductor device, and the second doped well-region and the second stressor structure collectively act as a second backgate to the at least one n-type conductivity type semiconductor device, and
wherein the first stressor structure includes an intrinsic tensile stressor structure comprising a tensile layer in the first region of the dielectric layer for inducing a compressive stress on the p-type conductivity type semiconductor device and the second stressor structure includes an intrinsic compressive stressor structure comprising a compressive layer in the second region of the dielectric layer for inducing a tensile stress on the n-type conductivity type semiconductor device.
2. The method of claim 1 , wherein said forming the at least one semiconductor device comprises:
providing a semiconductor on insulator (SOI) substrate, wherein a buried insulating layer of the SOI substrate provides the dielectric layer;
patterning a semiconductor layer of the SOI substrate to provide said first semiconductor island on the first region of the dielectric layer that is isolated from said second semiconductor island on the second region of the dielectric layer;
forming the p-type conductivity type semiconductor device on the first semiconductor portion in the first device region; and
forming the n-type conductivity type semiconductor device on the second semiconductor portion in the second device region.
3. The method of claim 2 , further comprising forming an interlevel dielectric layer on the p-type conductivity type semiconductor device and the n-type conductivity type semiconductor device.
4. The method of claim 3 further comprising:
bonding a handling substrate to the interlevel dielectric layer;
cleaving a base semiconductor layer of the SOI substrate to remove a first portion of the base semiconductor layer, wherein a second portion of the base semiconductor layer remains on the surface of the dielectric layer; and
removing the second portion of the base semiconductor layer.