Double-sided capacitor and fabrication method thereof

A fabrication method for a double-sided capacitor, comprising the following steps:

• providing a substrate, wherein a capacitor contact pad is formed on a surface of the substrate;
• forming a stack structure on the substrate to cover the capacitor contact pad;
• forming a capacitor hole in a direction perpendicular to the substrate to penetrate the stack structure and expose the capacitor contact pad, wherein the stack structure comprises sacrificial layers and supporting layers alternately stacked;
• forming an auxiliary layer to cover a sidewall of the capacitor hole;
• forming a first electrode layer to cover a surface of the auxiliary layer and the exposed capacitor contact pad;
• removing a part of the supporting layer on a top of the stack structure to form an opening to expose the sacrificial layers;
• removing the sacrificial layers and the auxiliary layer simultaneously along the opening to form a gap between the supporting layers and the first electrode layer;
• and
• forming a dielectric layer covering a surface of the first electrode layer and a second electrode layer covering a surface of the dielectric layer, wherein the gap is at least filled with the dielectric layer.