Horizontal-trench capacitor

A method of forming a capacitor, the method comprising the steps of:

• forming alternating nanosheets of a sacrificial material and an active material on a wafer, wherein the sacrificial material comprises SiGe, and wherein the active material comprises Si;
• patterning the nanosheets into at least one fin stack;
• burying the at least one fin stack in an ILD;
• removing the ILD from a first side of the at least one fin stack, forming a first cavity in which ends of the nanosheets of the active material are exposed;
• filling the first cavity with a semiconductor material that interconnects the nanosheets of the active material;
• implanting ions into the nanosheets, the semiconductor material and the wafer;
• annealing the nanosheets, the semiconductor material and the wafer;
• removing the ILD from a second side of the at least one fin stack forming a second cavity in which ends of the nanosheets of the active material are exposed;
• selectively removing the nanosheets of the sacrificial material, creating gaps between the nanosheets of the active material;
• depositing a dielectric into and lining the gaps and the second cavity;
• and
• filling the gaps and the second cavity with a conductor, wherein the conductor is interdigitated with the nanosheets of the active material, wherein the nanosheets of the active material and the semiconductor material serve as a cathode of the capacitor, and wherein the conductor serves as an anode of the capacitor.

A capacitor, comprising:

• nanosheets of an active material on a wafer, wherein the active material is selected from the group consisting of:
• Si and SiGe, and wherein gaps are present between the nanosheets of the active material;
• a semiconductor material interconnecting the nanosheets of the active material;
• ions implanted into the nanosheets of the active material, the semiconductor material and the wafer;
• a dielectric lining the gaps in the nanosheets of the active material;
• and
• a conductor filling the gaps, wherein the conductor is interdigitated with the nanosheets of the active material, wherein the nanosheets of the active material and the semiconductor material serve as a cathode of the capacitor, and wherein the conductor serves as an anode of the capacitor.