High density capacitor structure and method
High density capacitor structures based on an array of semiconductor nanorods are provided. The high density capacitor structure can be a plurality of capacitors in which each of the semiconductor nanorods serves as a bottom electrode for one of the plurality of capacitors, or a large-area metal-insulator-metal (MIM) capacitor in which the semiconductor nanorods serve as a support structure for a bottom electrode of the MIM capacitor subsequently formed.
1. A semiconductor structure comprising a plurality of capacitors, the plurality of capacitors comprising:
a plurality of semiconductor nanorods present on and oriented perpendicular to a top surface of a semiconductor substrate;
a conformal dielectric material layer present on exposed portions of the top surface of the semiconductor substrate and around sidewalls of the plurality of semiconductor nanorods; and
a conductive material layer located on the conformal dielectric material layer, the conductive material layer laterally surrounding the plurality of semiconductor nanorods and having a top surface coplanar with a top surface of the conformal dielectric material layer, wherein the conductive material layer is entirely composed of an electrically conductive material.
2. The semiconductor structure of claim 1 , wherein each of the plurality of semiconductor nanorods has a same crystal orientation as that of the semiconductor substrate.
3. The semiconductor structure of claim 1 , wherein the plurality of semiconductor nanorods comprises a semiconductor material the same as a semiconductor material of the semiconductor substrate.
4. The semiconductor structure of claim 1 , wherein the conformal dielectric material layer comprises silicon nitride, hafnium oxide, aluminum oxide, titanium oxide, or tantalum oxide.
5. The semiconductor structure of claim 1 , wherein the conductive material layer comprises tungsten, titanium, tantalum, aluminum, copper, an alloy thereof, a conductive metal nitride, a conductive metal oxide, or doped polysilicon.
6. The semiconductor structure of claim 1 , further comprising a plurality of first contact structures extending through a contact level dielectric layer and contacting the plurality of semiconductor nanorods, and a second contact structure extending through the contact level dielectric layer and contacting the conductive material layer.
7. The semiconductor structure of claim 6 , each of the plurality of the semiconductor nanorods further comprises a catalyst dot present on a top surface of each of the plurality of semiconductor nanorods, wherein each of the plurality of first contact structures contact one of the catalyst dots.
8. The semiconductor structure of claim 7 , wherein each catalyst dot comprises gold, aluminum, titanium, indium, iron or nickel.
9. The semiconductor structure of claim 7 , wherein each catalyst dot has a diameter ranging from 1 nm to 100 nm.
10. The semiconductor structure of claim 9 , wherein each of the plurality of the semiconductor nanorods has a diameter the same as the diameter of each catalyst dot.
11. The semiconductor structure of claim 1 , wherein each of the plurality of the semiconductor nanorods has a height ranging from 10 μm to 100 μm.
12. The semiconductor structure of claim 1 , wherein each of the plurality of semiconductor nanorods comprises an intrinsic semiconductor material.
13. The semiconductor structure of claim 1 , wherein the semiconductor substrate has a (111) crystal orientation.