Transistor with improved self-aligned contact
Systems, methods, and devices facilitating a transistor with an improved self-aligned contact are provided. In one example, a method comprises depositing a dielectric layer onto a first gate region and a second gate region of a semiconductor device, wherein the first gate region and the second gate region are separated by a substrate contact region, and wherein the dielectric layer has a first etch sensitivity to an inter-layer dielectric; and depositing a sacrificial layer onto the dielectric layer, wherein the sacrificial layer has a second etch sensitivity to the inter-layer dielectric that is greater than the first etch sensitivity.
1. A semiconductor device, comprising:
a substrate;
a contact cap on a gate surface of the semiconductor device, wherein the contact cap extends from the gate surface to a first distance from the substrate of the semiconductor device;
a substrate contact on a non-gate surface of the semiconductor device, wherein the substrate contact extends from the substrate of the semiconductor device to a second distance from the substrate of the semiconductor device that is greater than the first distance; and
a second contact on the substrate contact, wherein the second contact encapsulates all portions of the substrate contact that extend beyond the first distance.
2. The semiconductor device of claim 1 , wherein the gate surface comprises a metal gate surface and at least one spacer surface.
3. The semiconductor device of claim 2 , wherein the metal gate surface extends further from the substrate of the semiconductor device than the at least one spacer surface.
4. The semiconductor device of claim 1 , further comprising:
an inter-level dielectric on at least a portion of the contact cap, the inter-level dielectric comprising a trench that defines an area of the second contact.
5. The semiconductor device of claim 4 , wherein the trench is formed into the inter-level dielectric at the area of the second contact by reactive-ion etching.
6. A semiconductor device comprising:
a substrate;
a gate region on the substrate that extends from the substrate to a first distance from the substrate;
a contact cap that extends from the gate region to a second distance from the substrate;
a substrate contact that is physically separate from the gate region, and adjacent to the gate region, wherein the substrate contact extends a third distance from the substrate that is longer that the second distance;
a contact liner that separates the substrate contact from the substrate and the gate regions; and
a second contact that encapsulates all portions of the substrate contact that extend beyond the second distance.
7. The semiconductor device of claim 6 , wherein the contact cap comprises silicon nitride.