Semiconductor device and method of fabricating the same

A method of fabricating a semiconductor device, comprising:

• providing a semiconductor substrate and performing floating-gate polycrystalline silicon (poly-Si) deposition on the semiconductor substrate, thereby forming a first poly-Si layer, wherein the semiconductor substrate comprises a first patterned region and a second patterned region, the first patterned region having a feature density higher than a feature density of the second patterned region;
• performing ion implantation on the first poly-Si layer and forming an oxide layer over a top surface of the first poly-Si layer;
• with the oxide layer in the second patterned region being protected, etching the oxide layer in the first patterned region;
• performing a chemical mechanical polishing (CMP) process on the first poly-Si layer in the first patterned region and on the oxide layer and the first poly-Si layer in the second patterned region;
• and
• forming the semiconductor device on the basis of the first poly-Si layer that has undergone the CMP process.