A polysilicon structure and method of forming the polysilicon structure are disclosed, where the method includes a two-step deposition and planarization process. The disclosed process reduces the likelihood of defects such as voids, particularly where polysilicon is deposited in a trench having a high aspect ratio. A first polysilicon structure is deposited that includes a trench liner portion and a first upper portion. The trench liner portion only partially fills the trench, while the first upper portion extends over the adjacent field isolation structures. Next, at least a portion of the first upper portion of the first polysilicon structure is removed. A second polysilicon structure is then deposited that includes a trench plug portion and a second upper portion. The trench is filled by the plug portion, while the second upper portion extends over the adjacent field isolation structures. The second upper portion is then removed.