Memory device and method for manufacturing the same

A method for manufacturing a memory device, comprising:

• providing a substrate, wherein an array region of the substrate comprises a central region and a boundary region surrounding the central region, and wherein the substrate comprises a first active region and a second active region separated by an isolation structure;
• sequentially forming a bit line contact and a bit line structure over the first active region of the substrate;
• conformally forming a dielectric liner on the substrate to cover sidewalls of the bit line contact and the bit line structure and a top surface of the bit line structure;
• performing an etching process on the substrate to form a trench and expose the second active region;
• performing an ion implantation process in the trench located in the boundary region of the substrate to form an insulating layer at a bottom of the trench and covering the second active region;
• and
• forming a capacitor contact structure over the second active region.