Various embodiments of the present application are directed to a method of forming an integrated circuit (IC). An isolation structure is formed between a logic region and a memory region of a substrate. A dummy structure is formed on the isolation structure and defines a dummy sidewall of the dummy structure facing the logic region. A boundary sidewall spacer is formed covering the dummy structure and at least partially defines a boundary sidewall of the boundary sidewall spacer facing the logic region. A protecting dielectric layer is formed on a top surface of the boundary sidewall spacer by converting an uppermost portion of the boundary sidewall spacer to the protecting dielectric layer. The protecting dielectric layer is removed, and a logic device structure is formed on the logic region.