Flash memory and method of forming the same

A method of forming a semiconductor device, comprising:

• forming an isolation structure between a plurality of active areas;
• forming semiconductor structures over the active areas, wherein a portion of each of the semiconductor structures is embedded in the isolation structure;
• forming sacrificial structures on the semiconductor structures;
• performing an ion implantation process to form implanted regions between portions of the semiconductor structures embedded in the isolation structure, wherein the implanted regions are disposed within an upper portion of the isolation structure;
• removing the sacrificial structures to form patterned semiconductor structures;
• forming a dielectric structure on the patterned semiconductor structure;
• and
• forming a control structure on the dielectric structure,
• wherein the ion implantation process comprises carbon ion implantation, and the step of forming the semiconductor structures comprises:
• forming a plurality of first trenches in the isolation structure, wherein the first trenches correspond to the active areas;
• forming a semiconductor material in the first trenches and over the isolation structure;
• removing a portion of the semiconductor material to form the semiconductor structures,
• wherein top surfaces of the semiconductor structures and top surfaces of the isolation structures are coplanar;
• and
• removing a portion of the isolation structure to form a plurality of second trenches between the semiconductor structures.