Method for forming a capacitor in a mixed mode circuit device by ion implantation

A method for forming a capacitor in a mixed mode circuit device by ion implantation, wherein the method is suitable for a substrate, the substrate has an isolation layer formed thereon, the method comprising:

• forming a conductive layer on the isolation layer;
• performing an ion implantation process to implant ions into the conductive layer, wherein the ions can react with the conductive layer;
• performing an annealing process to trigger a reaction between the implanted ions and ions of the conductive layer to form a dielectric layer within the conductive layer;
• and
• patterning the dielectric layer and the conductive layer, wherein an upper portion of the conductive layer above the dielectric layer serves as an upper electrode, and a lower portion of the conductive layer below the dielectric layer serves as a lower electrode.

A method for forming a capacitor with ion implantation, the method comprising:

• forming a conductive layer on an substrate;
• performing an ion implantation process to implant ions into the conductive layer, wherein the ions can react with the conductive layer;
• performing an annealing process to trigger a reaction between the implanted ions and ions of the conductive layer to form a dielectric layer within the conductive layer;
• and
• patterning the dielectric layer and the conductive layer, wherein an upper portion of the conductive layer above the dielectric layer serves as an upper electrode, and a lower portion of the conductive layer below the dielectric layer serves as a lower electrode.