| 摘要 |
PURPOSE: A flash memory device and a manufacturing method thereof are provided to form the surface of minimized grain size between a floating gate electrode and a tunnel oxide layer by forming the floating gate electrode into a double layer structure. CONSTITUTION: A flash memory device is provided with a semiconductor substrate(102), an isolation layer formed in the substrate and a plurality of floating gates(126) electrically isolated from each other. At this time, the floating gate is made of the first and second polysilicon layer(122,124). The second polysilicon layer is enclosed with the first polysilicon layer except its upper surface. A plurality of protrusions are formed on the upper surface of the second polysilicon layer. The flash memory device further includes a dielectric layer(128) on the floating gate and a control gate(130) on the dielectric layer. The gaps between the protrusions are filled with the dielectric layer.
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